JP6676951B2 - Display body - Google Patents

Description

  The present invention relates to a display that can be used to prevent forgery of an article.

  Securities such as gift certificates and checks, credit cards, cash cards, and cards such as ID cards, and certificates such as passports and licenses are usually printed on paper with ink or the like to prevent counterfeiting. A display body having a visual effect different from that of the printed matter is attached.

  Such a display body has, for example, a fine structure that is a plurality of fine projections or depressions, and has a shortest wavelength of visible light along each of a first direction and a second direction orthogonal to the first direction. The following display bodies having a plurality of fine structures arranged at equal intervals are known. This display body can display black in the direction in which the display body is viewed from the front by preventing reflection of light incident on the display body by a plurality of microstructures, and can display a plurality of finely arranged pixels arranged periodically. With the structure, a rainbow color can be displayed by diffracted light in a direction oblique to the display body (for example, see Patent Documents 1 and 2).

Japanese Patent No. 4420138 Patent No. 4315334

  By the way, black display when the display is viewed from the front can be realized even when the amount of light incident on the display is small. On the other hand, the display of the rainbow color in the perspective of the display body is less visible as the amount of light incident on the display body is smaller. In the display body described above, in order to further enhance the effect of preventing counterfeiting of an article, it is preferable that the display in the front view and the display in the oblique view are clearly different even when the amount of light incident on the display body is small. Therefore, it is required to increase the brightness of the diffracted light.

  In addition, since the plurality of microstructures are arranged at equal intervals along each of the first direction and the second direction, the plurality of microstructures are arranged in a plurality of directions such as a direction substantially at 27 ° and a direction at 45 ° with respect to the first direction. Are also arranged at substantially equal intervals. Accordingly, the range of angles at which diffracted light emitted from the display body can be visually recognized is large. In the above-described display body, it is required to enhance the directivity of the diffracted light in the emission direction in order to differentiate the printed body from printed matter formed of ink or the like.

In addition, such a request is not limited to a display used for the purpose of suppressing counterfeiting of an article, but is also common to a display used for the purpose of decorating an article and a display which is an object to be observed. .
SUMMARY OF THE INVENTION It is an object of the present invention to provide a display that can increase the luminance of diffracted light while improving the directivity of the diffracted light in the emission direction.

  A display for solving the above-mentioned problem includes an uneven structure having an uneven surface as an incident surface on which light is incident, and the uneven surface is configured such that the convex surface and the concave surface are alternately repeated one by one along the arrangement direction. Each of the convex surfaces extends in a band along an extending direction orthogonal to the arrangement direction, and has a shape that tapers toward a top along a thickness direction of the concave-convex structure, and The concave portion extends in a strip shape along the extending direction, has a shape tapering toward the bottom along the thickness direction of the concave-convex structure, and the light incident on the concave-convex surface is formed on the concave-convex surface. A period in which the light incident on the uneven surface is emitted from the uneven surface as diffracted light in a direction oblique to the uneven surface, while suppressing reflection of the uneven surface in a direction viewed from the front. The convex surface and the concave surface are aligned at the It has the property of absorbing light incident on the concave-convex structure.

  According to the display, the convex surface and the concave surface are alternately arranged along the arrangement direction, and each convex surface and each concave surface extend along the extending direction. The diffracted light is emitted to a plane defined by a direction parallel to the thickness direction of the diffracted light, and as a result, the directivity of the diffracted light in the emission direction is enhanced. In addition, since each convex surface included in the uneven surface extends along the extending direction, diffracted light is emitted as compared with a configuration in which the convex surfaces are arranged at equal intervals along each of the extending direction and the arrangement direction. The brightness of the diffracted light emitted to the plane defined by the arrangement direction and the direction parallel to the thickness direction of the uneven structure can be increased by the amount of the surface that is continuous in the extending direction.

  In the display body, the light incident side with respect to the uneven surface is an observation side, a predetermined point located on the observation side is a first fixed point, and a position on the observation side is a second fixed point different from the first fixed point. Wherein the arrangement direction is a first arrangement direction, the extension direction is a first extension direction, the convex surface is a first convex surface, the concave surface is a first concave surface, and the first The direction that intersects the arrangement direction is the second arrangement direction. The uneven surface is divided into a plurality of pixels, and among the plurality of pixels, the first convex surface and the first concave surface are alternately arranged along the first arrangement direction, and diffracted toward the first fixed point. A pixel that emits light is a first array pixel, and the plurality of pixels are configured such that second convex surfaces and second concave surfaces are alternately arranged along the second array direction, and diffracted light toward the second fixed point. It may further include a second array pixel that is a pixel to emit light. Each of the second convex surfaces extends in a band shape along a second extending direction orthogonal to the second arrangement direction, and has a shape that tapers toward a top along a thickness direction of the concave-convex structure, Each of the second concave surfaces extends in a band along a second extending direction orthogonal to the second arrangement direction, and has a shape that tapers toward a bottom along a thickness direction of the uneven structure. Is preferred. Further, in the second array pixel, the light incident on the second array pixel is prevented from being reflected in a direction in which the second array pixel is viewed from the front, and the light incident on the second array pixel is suppressed. It is preferable that the second convex surface and the second concave surface are arranged in a cycle in which the light is emitted from the second array pixel as diffracted light in a direction oblique to the second array pixel.

  According to the above configuration, since the uneven surface includes the first array pixel that emits diffracted light toward the first fixed point and the second array pixel that emits diffracted light toward the second fixed point, the display body includes: With respect to the first fixed point and the second fixed point, an image can be displayed by diffracted light emitted from pixels different from each other.

  In the above-described display, the uneven surface includes a first region including a plurality of pixels and a second region including a plurality of pixels, and the first region includes at least the first array pixel. And the second region may include at least the second array pixel. The ratio of the sum of the areas of the first array pixels to the area of the first region and the ratio of the sum of the areas of the first array pixels to the area of the second region are different from each other. The ratio of the sum of the areas of the second array pixels to the area of one region and the ratio of the sum of the areas of the second array pixels to the area of the second region may be different from each other.

  According to the above configuration, since the brightness of the image is different from each other in the image displayed by the display toward the first fixed point and the image displayed toward the second fixed point, the display is displayed in the first area. And the image displayed in the second area can be displayed as an image visually separated at each fixed point.

  In the above-mentioned display, the period is a first period, the convex surface is a first convex surface, and the concave surface is a first concave surface. The uneven surface is divided into a plurality of pixels, and among the plurality of pixels, a pixel in which the first convex surface and the first concave surface are arranged in the first cycle along the arrangement direction is a first cycle pixel, The plurality of pixels may further include a second cycle pixel that is a pixel in which a second convex surface and a second concave surface are arranged in a second cycle different from the first cycle along the arrangement direction. Each of the second convex surfaces extends in a belt shape along the extending direction, has a shape tapering toward a top along a thickness direction of the concave-convex structure, and each of the second concave surfaces is It is preferable to have a shape that extends in a strip shape along the extending direction and tapers toward the bottom along the thickness direction of the uneven structure. Further, in the second periodic pixel, the light incident on the second periodic pixel is prevented from being reflected in a direction in which the second periodic pixel is viewed from the front, and the light incident on the second periodic pixel is suppressed. It is preferable that the second convex surface and the second concave surface are arranged in the second cycle in which the light is emitted from the second cycle pixel as diffracted light in a direction oblique to the second cycle pixel.

  According to the above configuration, the display includes a diffracted light emitted from the first periodic pixel toward a predetermined fixed point and a diffracted light emitted from the second periodic pixel toward the same fixed point. An image composed of the diffracted light emitted from the pixel and the diffracted light having a different color can be formed.

  In the above display, the uneven surface includes a first region including a plurality of pixels and a second region including a plurality of pixels, and the first region includes at least the first periodic pixel. And the second region may include at least the second periodic pixel. The ratio of the sum of the areas of the first periodic pixels in the first region to the sum of the areas of the second periodic pixels, the sum of the areas of the first periodic pixels in the second region, and the The ratio with the sum of the areas of the two-period pixels may be different from each other.

  According to the above configuration, since the color of light emitted from the first area toward a predetermined fixed point and the color of light emitted from the second area toward the same fixed point are different from each other, each area is displayed. The image displayed in the first area and the image displayed in the second area are more easily visually distinguished from each other than the configuration in which the brightness differs between the images.

  In the display, in the front view direction, brightness of an image displayed by the first region in the front view direction, and brightness of an image displayed by the second region in the front view direction. It is preferable that the concave and convex surface is configured such that is substantially equal to each other.

  According to the display, in the direction in which the display is viewed from the front, the image displayed by the display is visually recognized as one image. An image formed based on the difference between the characteristic of the diffracted light in the second region and the characteristic of the diffracted light in the second region can be hidden from the observer.

  ADVANTAGE OF THE INVENTION According to this invention, the brightness | luminance of diffracted light can be raised, raising the directivity in the emission direction of diffracted light.

FIG. 2 is a partial perspective view showing a partial perspective structure of a concave-convex surface provided in the display according to the first embodiment. FIG. 3 is a partial cross-sectional view illustrating a partial cross-sectional structure of a display body along a YZ plane. The figure which shows typically the mode that the diffraction grating which has a period larger than the shortest wavelength of visible light emits + 1st-order diffracted light. The figure which shows typically the mode that the diffraction grating which has a period smaller than the shortest wavelength of visible light emits + 1st-order diffracted light. FIG. 4 is an operation diagram for explaining the operation of the uneven surface when the uneven surface is perspectively viewed. FIG. 4 is an operation diagram for explaining the function of the uneven surface when the uneven surface is viewed from the front. The perspective view which shows the perspective structure in the display body of a prior art example. FIG. 7 is a plan view showing a planar structure of a display according to a second embodiment. FIG. 4 is a partially enlarged plan view showing a partially planar structure of a first region included in the uneven surface in an enlarged manner. FIG. 6 is a partially enlarged plan view showing a partially planar structure of a second region included in the uneven surface in an enlarged manner. FIG. 2 is a partial perspective view showing a partial perspective structure of a first uneven surface of a first pixel. FIG. 4 is a partial perspective view showing a partial perspective structure of a second uneven surface of a second pixel. FIG. 9 is a partial perspective view showing a partial perspective structure of a third uneven surface of a third pixel. FIG. 9 is a partial perspective view showing a partial perspective structure of a fourth uneven surface of a fourth pixel. FIG. 4 is an operation diagram for explaining the operation of the display when the display is obliquely viewed. FIG. 4 is an operation diagram for explaining the operation of the display when the display is obliquely viewed. FIG. 9 is an operation diagram for explaining the operation of the display when the display is viewed from the front. FIG. 4 is a cross-sectional view illustrating a cross-sectional structure of an example of a display body. FIG. 4 is a cross-sectional view illustrating a cross-sectional structure of an example of a display body. 4 is a graph showing the relationship between the amount of electron beam irradiation on polymethyl acrylate and the amount of polymethyl acrylate dissolved. FIG. 2 is a partial cross-sectional view showing a partial cross-sectional structure of the original plate formed by the first method, which is measured by an atomic force microscope. FIG. 6 is a partial cross-sectional view showing a partial cross-sectional structure of the original plate formed by the second method, which is measured by an atomic force microscope. FIG. 2 is a plan view showing a planar structure of an example of an article to which a display body is applied. FIG. 25 is a cross-sectional view showing the cross-sectional structure of the article along the line II in FIG. 24. FIG. 13 is a plan view showing a planar structure of a display according to a third embodiment. FIG. 4 is a partially enlarged plan view showing a partially planar structure of a first region included in the uneven surface in an enlarged manner. FIG. 6 is a partially enlarged plan view showing a partially planar structure of a second region included in the uneven surface in an enlarged manner. FIG. 6 is a partially enlarged plan view showing a partially planar structure of a third region included in the uneven surface in an enlarged manner. FIG. 6 is a partially enlarged plan view showing a partially planar structure of a fourth region included in the uneven surface in an enlarged manner. FIG. 4 is an operation diagram for explaining the operation of the display when the display is obliquely viewed. FIG. 4 is an operation diagram for explaining the operation of the display when the display is obliquely viewed. FIG. 9 is an operation diagram for explaining the operation of the display when the display is viewed from the front.

[First Embodiment]
A first embodiment of a display according to the present invention will be described with reference to FIGS. Hereinafter, the configuration of the display and the operation of the display will be described in order.

[Configuration of display body]
The configuration of the display will be described with reference to FIG.
As shown in FIG. 1, the display body 10 includes an uneven structure 11, and the uneven structure 11 has an uneven surface 11 s as an incident surface on which light enters. In the uneven surface 11s, the convex surface 11a and the concave surface 11b are alternately repeated one by one along the Y direction, which is one example of the arrangement direction.

  Each convex surface 11a is an example of the extending direction, extends in a band shape along the X direction orthogonal to the Y direction, and is a direction parallel to the thickness direction of the concave-convex structure 11, the X direction and the Y direction. Are tapered toward the top 11c along the Z direction orthogonal to both of them. In each convex surface 11a, the length along the X direction is sufficiently longer than the length along the Y direction. The shape of each convex surface 11a is substantially equal to the shape of the other remaining convex surfaces 11a.

  Each concave surface 11b has a shape extending in a band shape along the X direction and tapering toward the bottom 11d along the Z direction. In each concave surface 11b, the length along the X direction is sufficiently longer than the length along the Y direction. In the Z direction, the distance between the top 11c of the convex surface 11a and the bottom 11d of the concave surface 11b is the height H of the uneven surface 11s.

  The tops 11c are arranged with a predetermined pitch P in the Y direction. That is, the pitch P is the distance between two adjacent tops 11c in the Y direction. In a structure defined by one convex surface 11a and two concave surfaces 11b sandwiching one convex surface 11a in the Y direction, the maximum value of the width along the Y direction is the maximum width W, and the maximum width W is equal to the pitch P. equal.

  In the uneven surface 11s, the length of the repeating unit of the convex surface 11a and the concave surface 11b along the Y direction is the period d. In the uneven surface 11s, the period d and the pitch P have the same value. Note that the period d and the pitch P need not be equal to each other. For example, the pitch P of the uneven surface 11s includes a first pitch and a second pitch different from the first pitch, and the first pitch and the second pitch are alternately arranged in the Y direction. There may be. In such a configuration, the convex surface 11a and the concave surface 11b that are adjacent in the Y direction are a set of concave and convex surfaces, and the repeating unit is composed of two sets of concave and convex surfaces that are adjacent in the Y direction. This is the sum with the second pitch.

  Further, for example, in the uneven surface 11s, the tops 11c are arranged at a predetermined pitch P, while the distance between the top 11c and the bottom 11d is the first height and the unevenness between the top 11c and the bottom 11d. The uneven surfaces having a second height different from the first height may be alternately arranged along the Y direction. In such a configuration, the repeating unit is composed of two sets of concavo-convex surfaces adjacent in the Y direction, and the period d is twice the pitch P.

  The uneven surface 11s is configured to suppress the incident light on the uneven surface 11s from being reflected in a front view direction, which is a direction in which the uneven surface 11s is viewed from the front, and the uneven surface 11s has an uneven surface. It is configured such that incident light on the surface 11s is emitted as diffracted light in a direction oblique to the uneven surface 11s.

  That is, the uneven surface 11s suppresses the light incident on the uneven surface 11s from being reflected in the front view direction, which is the direction in which the uneven surface 11s is viewed from the front, and reduces the light incident on the uneven surface 11s. The convex surface 11a and the concave surface 11b are arranged in a cycle of emitting diffracted light in a direction oblique to the surface 11s. The uneven structure 11 has a characteristic of absorbing light incident on the uneven structure 11.

  The pitch P at the top 11c of the convex surface 11a is not less than 200 nm and not more than 500 nm, and preferably not more than the shortest wavelength of visible light, for example, not more than 400 nm. The plurality of convex surfaces 11a have a distance between the adjacent tops 11c. They are arranged regularly along the Y direction so as to have a pitch P. Further, the pitch P at the bottom 11d of the concave surface 11b is not less than 200 nm and not more than 500 nm, and is preferably not more than the shortest wavelength of visible light, for example, not more than 400 nm, and the plurality of concave surfaces 11b are located between the adjacent bottoms 11d. They are regularly arranged along the Y direction so that the distance is the pitch P. In the uneven surface 11s, a plurality of convex surfaces 11a having substantially the same shape and a plurality of concave surfaces 11b having substantially the same shape are regularly arranged, so that the uneven surface 11s functions as a diffraction grating.

  The height H of the uneven surface 11s is preferably equal to or more than １ ／ of the pitch P of the convex surface 11a. If the height H of the uneven surface 11s is equal to or more than の of the pitch P, the uneven surface 11s suppresses reflection of incident light in the direction in which the display body 10 is viewed from the front, that is, in the Z direction. be able to. Further, the configuration in which the height H of the uneven surface 11s is larger than the pitch P is more preferable than the configuration in which the height H of the uneven surface 11s is equal to or less than the pitch P in that the reflection of incident light can be suppressed. That is, the height H of the uneven surface 11s is preferably 200 nm or more, and more preferably 500 nm or more.

  Further, in forming the uneven surface 11s with such an accuracy that the function of suppressing the reflection by the uneven surface 11s and the function of emitting the diffracted light is sufficient, the height H of the uneven surface 11s is 750 nm or less. Preferably, there is.

  Each convex surface 11a is a tapered surface tapering toward the top 11c, and each concave surface 11b is a tapered surface tapering toward the bottom 11d. In the structure defined by the uneven surface 11s, the cross-sectional shape along the YZ plane is a plurality of substantially triangular shapes, including a shape in which each vertex of the triangle has a curvature, and the cross-sectional shape along the YZ plane is It is continuous along the X direction.

  In the structure defined by the uneven surface 11s, each shape included in the cross-sectional shape along the YZ plane may be equal to the cross-sectional shape along the plane passing through the central axis in the following shapes, and May be continuous along the X direction. That is, each shape included in the cross-sectional shape along the YZ plane may be equal to the cross-sectional shape along a plane passing through the central axis in a half spindle shape, a cone shape, and a truncated cone shape, and In the structure defined by the uneven surface 11s, the sectional shape along the YZ plane may be continuous along the X direction. Note that the cone shape is, for example, a cone shape or a pyramid shape, and the truncated cone shape may be a truncated cone shape, a truncated pyramid shape, or the like. Further, each of the convex surface 11a and the concave surface 11b may be a step surface having a step shape in the Z direction.

  As shown in FIG. 2, in the uneven surface 11s, the curvature at the top 11c of the convex surface 11a and the curvature at the bottom 11d of the concave surface 11b are equal to each other, and the curvature of the top 11c and the curvature of the bottom 11d are the same. Is larger than the curvature at portions other than the top 11c and the bottom 11d.

In the convex surface 11a, in a cross section along the YZ plane, an angle formed by a tangent to the top 11c and a tangent to a portion other than the top 11c is an inclination angle θ, and the inclination angle θ suppresses reflection of light along the Z direction. Above, it is preferable that it is 50 degrees or more and 80 degrees or less.
In the uneven surface 11s, the slope S in the Z direction on the surface connecting the top 11c and the bottom 11d can be defined by the following equation (1).
S = | log ₁₀ (Wb / Wt) | ^-1 (1)

  In the formula (1), the bottom width Wb is equal to or smaller than the bottom 11d in the Z direction of the structure defined by the two concave surfaces 11b adjacent in the Y direction and the convex surface 11a connecting the two concave surfaces 11b. Is the width of the structure at a position close to the top 11c by 0.1 × H. The top width Wt is the width of the structure at a position closer to the top 11c by 0.9 × H than the bottom 11d in the Z direction. S is preferably smaller than 25, and according to the uneven surface 11s in which S is smaller than 25, the area of the plane forming the top 11c of the convex surface 11a and the area of the plane forming the bottom 11d of the concave surface 11b are: This is a preferable size for suppressing the reflection of light on the uneven surface 11s.

[Function of display body]
The operation of the display 10 will be described with reference to FIGS. In the following, prior to the description of the operation of the display 10, the diffraction grating will be described.

[Diffraction grating]
The diffraction grating emits diffracted light having high luminance in a predetermined direction with respect to the traveling direction of the illumination light that is incident light. The exit angle β of the m-th order diffracted light (m = 0, ± 1, ± 2,...) is given by the following formula (2) when the light travels in a plane perpendicular to the length direction of the groove of the diffraction grating. ) Can be calculated.
d = mλ / (sin α−sin β) Equation (2)

  In equation (2), d is the period of the diffraction grating, m is the diffraction order, and λ is the wavelength of the incident light and the wavelength of the diffracted light. Α is the zero-order diffracted light, which is the exit angle of the transmitted light or the specularly reflected light. In other words, the absolute value of α is equal to the incident angle of the illumination light, and in the reflection type diffraction grating, the incident direction of the illumination light and the emission direction of the specularly reflected light are in the front view direction, which is the direction in which the diffraction grating is viewed from the front. Symmetric to it.

  When the diffraction grating is a reflection type, the angle α is 0 ° or more and less than 90 °. The front view direction, that is, 0 ° is a boundary value, and when the diffraction grating is irradiated with illumination light from an oblique direction, the range of angles including the emission direction of the specularly reflected light is a positive angle range, and the illumination light Is a negative angle range. When the emission direction of the diffracted light is included in the same angle range as the emission direction of the specularly reflected light, that is, when included in the positive angle range, the angle β is a positive value. On the other hand, when the output direction of the diffracted light is included in the same angle range as the incident direction of the illumination light, that is, when the output direction is included in the negative angle range, the angle β is a negative value.

  When the observer looks at the diffraction grating from the front, of the diffracted light emitted by the diffraction grating, the diffracted light that contributes to the display of an image visually recognized by the observer is only the diffracted light having an emission angle β of 0 °. . Therefore, when the period d is larger than the wavelength λ, there are a wavelength λ and an incident angle α that satisfy the above equation (2). Therefore, the observer can visually recognize the diffracted light having the wavelength λ satisfying the expression (2).

  On the other hand, when the period d is smaller than the wavelength λ, there is no incident angle α that satisfies the expression (2), so that an observer looking at the diffraction grating in front cannot see the diffracted light.

  That is, among the diffraction gratings, a diffraction grating having a small period d, that is, a diffraction grating having a period d smaller than the wavelength λ does not emit diffracted light in the front view direction and has a period d of approximately the wavelength λ. The grating emits only diffracted light that is almost invisible in the front view direction.

  The above-described diffraction grating will be described in further detail with reference to FIGS. FIG. 3 shows a diffraction grating having a period d larger than the shortest wavelength of visible light, and FIG. 4 shows a diffraction grating having a period d smaller than the shortest wavelength of visible light. 3 and 4 show only the red diffracted light, the green diffracted light, and the blue diffracted light as the first-order diffracted light emitted from the diffraction grating for convenience of description and illustration.

  As shown in FIG. 3, the diffraction grating DG has a period d larger than the shortest wavelength of visible light, for example, 400 nm. The illumination light IL emitted by the light source LS is white light composed of a plurality of lights having a plurality of different wavelengths. When the illumination light IL is incident on the diffraction grating DG from an oblique direction, the diffraction grating DG The emitted light RL that is the reflected light or the zero-order diffracted light is emitted.

  Further, the diffraction grating DG emits red diffracted light DLr, green diffracted light DLg, and blue diffracted light DLb, in which the illumination light IL is separated, as the first-order diffracted light. Each of the exit angle βr of the red diffracted light DLr, the exit angle βg of the green diffracted light DLg, and the exit angle βb of the blue diffracted light DLb are positive values included in a positive angle range with respect to the front view direction DLV. is there.

  On the other hand, as shown in FIG. 4, the diffraction grating DG is larger than の of the shortest wavelength of visible light and smaller than the shortest wavelength of visible light, that is, larger than 200 nm, and It has a period d smaller than 400 nm.

  When the illumination light IL is incident on the diffraction grating DG from an oblique direction, the diffraction grating DG has red diffraction light DLr and green diffraction light DLg as first-order diffraction light, similarly to the diffraction grating DG described above with reference to FIG. , And blue diffracted light DLb. However, the emission angle βr of the red diffracted light DLr, the emission angle βg of the green diffracted light DLg, and the emission angle βb of the blue diffracted light DLb are negative values.

  For example, when the incident angle α of the illumination light IL is 50 ° and the period d is 330 nm, the diffraction grating DG outputs light having a wavelength of 540 nm, which is green light, of the illumination light IL. The green diffracted light DLg is emitted as the next diffracted light, and the emission angle βg of the green diffracted light DLg is −60 °.

[Display body]
The operation of the display 10 will be described with reference to FIGS.
As shown in FIG. 5, on the uneven surface 11s of the display body 10, a plurality of tops 11c are arranged at a predetermined period d, that is, at a predetermined pitch P along the Y direction, and the period d is 200 nm or more and 500 nm or less. . Further, the plurality of convex surfaces 11a and the plurality of concave surfaces 11b have a band shape extending along the X direction.

  Therefore, when the white illumination light IL emitted by the light source LS enters the uneven surface 11s from an oblique direction, the uneven surface 11s emits the diffracted light DL in the YZ plane YZ including the front view direction DLV. Moreover, the diffracted light DL is emitted on the YZ plane YZ on the side opposite to the emission light RL with respect to the front view direction DLV. Alternatively, in the YZ plane YZ, the diffracted light DL is emitted to the same side as the emission light RL with respect to the front view direction DLV to the extent that the diffracted light DL is hard to be visually recognized, while being diffracted to the opposite side with respect to the front view direction DLV. Is emitted to the extent that it is easily visible.

  In order to suppress that the diffracted light DL is reflected on the same side as the emission light RL in the front-view direction DLV in the YZ plane YZ, the period d in the uneven surface 11s is 200 nm or more and 400 nm or less. Is preferred.

  As described above, since the display body 10 having the uneven surface 11s emits the diffracted light DL on the YZ plane YZ orthogonal to the direction in which the convex surface 11a extends, the directivity of the diffracted light DL emitted from the display body 10 is enhanced. Can be Moreover, since the diffracted light DL is emitted from the uneven surface 11s formed of the convex surface 11a and the concave surface 11b extending along the X direction, the surface for emitting the diffracted light is discretely arranged along the X direction. Compared to the arrangement, the intensity of the diffracted light in the direction of emission of the diffracted light is increased.

  Here, when an article, in particular, a light-absorbing article, and an article having a low luminance of reflected light or scattered light emitted from the article is observed by an observer, the observer generally emits light from the article. The article and the light source are relatively positioned with respect to the observer's viewpoint so that the specularly reflected light can be visually recognized.

  As described above, according to the display body 10, the diffracted light emitted from the display body 10 is emitted to the side opposite to the emission light RL including the regular reflection light with respect to the front view direction DLV. Therefore, even if the observer who does not know in advance the direction in which the diffracted light DL is emitted is likely to be unable to visually recognize the diffracted light emitted from the display body 10 even when observing the display body 10. As a result, it is difficult for an observer to recognize that the display body 10 has a function of emitting diffracted light.

  On the other hand, in the configuration in which the diffracted light is emitted to the same side as the specularly reflected light with respect to the front view direction, the viewer does not need to know beforehand that the display has a function of emitting the diffracted light. Thus, it is highly possible that an observer can visually recognize the diffracted light emitted from the display body.

  As shown in FIG. 6, among the uneven surfaces 11s, the convex surface 11a has a tapered shape tapering toward the top 11c, and the concave surface 11b has a tapered shape tapering toward the bottom 11d. Further, in the uneven surface 11s, the tops 11c are arranged at a pitch P of 200 nm or more and 500 nm or less. Accordingly, when the display 10 is viewed from the light incident side with respect to the uneven surface 11s of the display 10 according to the principle described below, the display 10 emits from the display 10 regardless of the viewing angle. The reflectance of the specularly reflected light decreases.

  Here, since the light is reflected at the interface where the refractive index changes intermittently, if the area of the flat surface is small at each of the top 11c of the convex surface 11a and the bottom 11d of the concave surface 11b, the light reflection amount at this site is small. Become.

  In addition, if the pitch P of the convex surface 11a is substantially equal to or less than the resolution limit of the wavelength, the refractive index when cut in a horizontal plane with respect to the direction of light entry, that is, the depth direction of the convex surface 11a, becomes Is determined by the ratio of the air around the concave-convex structure 11 to the air around the concave-convex structure 11.

  At this time, if the change in the shape of the convex surface 11a with respect to the depth direction of the convex surface 11a is substantially continuous, the refractive index in the horizontal plane described above also changes uniformly and continuously according to the depth of the convex surface 11a. Thus, the influence of the interface of the refractive index that causes the reflection of light at the inclined portion of the convex surface 11a is reduced.

  The uneven structure 11 has a characteristic of absorbing light incident on the uneven structure 11. In other words, the uneven structure 11 has a portion that absorbs light transmitted through the uneven surface 11s and a portion that absorbs light on the side opposite to the light incident side, with respect to the uneven surface 11s that is a light incident surface. What is necessary is just to have the transparency which transmits. In other words, the concavo-convex structure 11 has a portion that converts light transmitted through the concavo-convex surface 11s into thermal energy inside the concavo-convex structure 11, and a transmittance that transmits light to a portion that converts light into heat energy. Just do it.

  In addition, the portion of the concave-convex structure 11 that absorbs light may have a function of reflecting light, and any configuration may be used as long as light incident on the absorption portion is absorbed by multiple reflections in the concave-convex structure 11.

  Then, as described above, the display body 10 emits diffracted light that is easily viewed by an observer on the side opposite to the specularly reflected light with respect to the front view direction of the display body 10, while, in the front view direction, Does not emit diffracted light substantially.

  For this reason, the display 10 displays, for example, an image having black or an image having gray in the front view direction. In addition, black means that, when white light is irradiated from the front view direction and the intensity of specular reflection light is measured, the reflectance is 10% or less for all wavelengths included in the range of 400 nm to 700 nm. State. Further, gray means that when white light is emitted from the front view direction and the intensity of specularly reflected light is measured, the reflectance of all the wavelengths included in the range of 200 nm or more and 700 nm or less is more than 10%. This is a state where it is about 25% or less.

  In order to display an image having black color on the display 10, it is preferable that the height H of the uneven surface 11 s be larger in that the change rate of the refractive index along the Z direction on the uneven surface 11 s becomes smaller. On the other hand, as the height of the uneven surface 11s is lower, the reflectance on the uneven surface 11s increases, and the brightness of the image displayed by the display body 10 increases. As a result, the display 10 displays an image having gray.

  For example, when the pitch P is 500 nm, as described above, when the height H of the uneven surface 11s is 250 nm or more, the display 10 displays a gray image. Then, as the height H of the uneven surface 11s increases, the display body 10 can display an image with low brightness. When the height of the uneven surface 11s is 500 nm or more, the display body 10 becomes substantially black. The held image can be displayed.

On the other hand, when the height of the uneven surface 11s exceeds 750 nm, that is, on the uneven surface 11s having an aspect ratio larger than 1.5, the display body 10 displays even if the height H of the uneven surface 11s increases. The brightness of the image remains almost unchanged. In addition, when the aspect ratio exceeds 1.5, it becomes more difficult to form the concavo-convex structure 11 with high accuracy as compared with a configuration in which the aspect ratio is 1.5 or less.
For these reasons, as described above, the height H of the uneven surface 11s is preferably 200 nm or more and 750 nm or less.

  On the other hand, as shown in FIG. 7, the conventional display body 20 includes the uneven structure 21, and the uneven surface 21 s of the uneven structure 21 that is the light incident surface has the following configuration. That is, the uneven surface 21s has a plurality of convex surfaces 21a, and the plurality of convex surfaces 21a are regularly arranged along the X direction, and are regularly arranged along the Y direction.

  Since the convex surfaces 21a are regularly arranged along each of the X direction and the Y direction, the display body 20 can emit diffracted light. However, the convex surfaces 21a are discretely arranged along each of the X direction and the Y direction. Therefore, as compared with the configuration having the convex surface 11a extending along the X direction as in the display body 10 described above, the area of the surface that emits the diffracted light toward the YZ plane is smaller, so that the light is emitted toward the YZ plane. The brightness of the diffracted light becomes lower.

  In addition, since the plurality of convex surfaces 21a are regularly arranged along each of the X direction and the Y direction, the plurality of convex surfaces 21a are almost even in a plurality of directions such as a direction of approximately 27 ° and a direction of 45 ° with respect to the X direction. They are arranged regularly. Accordingly, the range of angles at which diffracted light emitted from the display 20 can be visually recognized is larger than that of the display 10 described above.

As described above, according to the first embodiment of the display, the following effects can be obtained.
(1) Since the convex surfaces 11a and the concave surfaces 11b are alternately arranged along the Y direction, and each convex surface 11a and each concave surface 11b extend along the X direction, the concave and convex surface 11s emits diffracted light to the YZ plane. As a result, the directivity of the diffracted light in the emission direction is enhanced. Further, since each convex surface 11a and each concave surface 11b included in the uneven surface 11s extend along the X direction, the convex surfaces are arranged at equal intervals along each of the X direction and the Y direction, Since the surface from which the diffracted light is emitted is continuous in the X direction, the luminance of the diffracted light emitted on the YZ plane can be increased.

[Modification of First Embodiment]
The above-described first embodiment can also be implemented with appropriate modifications as described below.
Each of the top 11c and the bottom 11d may be formed of a flat surface. In the first embodiment described above, since each of the top 11c and the bottom 11d is formed of a surface having a curvature, the pitch P at which the tops 11c are arranged is equal to the maximum width W. However, when each of the top 11c and the bottom 11d is formed of a flat surface, the pitch P at which the tops 11c are arranged is larger than the maximum width W.

  The height H of the uneven surface 11s may include a plurality of different values. As described above, the effect of suppressing the reflection of incident light between the portion having the first height and the portion having the second height different from the first height in the uneven surface 11s. Are different from each other. Therefore, in order to equalize the effect of suppressing the reflection of the incident light on the entire uneven surface 11s, that is, the variation in the brightness is suppressed within the image displayed by the display body 10 in the front view direction of the display body 10. Above, it is preferable that the height of the uneven surface 11s be substantially equal in the entire uneven surface 11s.

[Second embodiment]
A second embodiment that embodies the display of the present invention will be described with reference to FIGS. Since the display of the second embodiment includes the same configuration as the display of the first embodiment described above, the same components as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment. Accordingly, a detailed description of a configuration common to the first embodiment will be omitted. In the second embodiment, an example will be described in which the pitch and the period on the uneven surface have the same value.
Hereinafter, the configuration of the display, the operation of the display, the method of manufacturing the display, and the configuration of the article to which the display is applied will be sequentially described.

[Configuration of display body]
The configuration of the display will be described with reference to FIGS.
As shown in FIG. 8, the display body 10 has an uneven surface 11s that is a light incident surface, and the uneven surface 11s includes a first region 11s1 and a second region 11s2. Each of the first region 11s1 and the second region 11s2 includes a plurality of convex surfaces and a plurality of concave surfaces.

  The light incident side with respect to the uneven surface 11s is the observation side, and a predetermined point located on the observation side is a fixed point. Since the luminance of the diffracted light emitted from the first region 11s1 toward the fixed point and the luminance of the diffracted light emitted from the second region 11s2 toward the fixed point are different from each other, the image displayed on the first region 11s1 is different from the image displayed on the first region 11s1. The uneven surface 11s is configured so that the image displayed by the second region 11s2 is visually separated at a fixed point. The luminance of the diffracted light is a first characteristic, and the first characteristic is included in the characteristic of the diffracted light.

  For the observer who observes the display body 10 from a fixed point on the observation side, the display body 10 is configured to determine the luminance of the diffracted light emitted from the first area 11s1 and the luminance of the diffracted light emitted from the second area 11s2. An image formed based on the difference can be displayed. Therefore, as compared with a configuration in which one type of diffracted light is emitted from the entire uneven surface 11s, an image displayed in the direction in which the uneven surface 11s is perspective becomes more complicated among images displayed by the uneven surface 11s.

  Further, in the display body 10, in the direction in which the display body 10 is viewed from the front, the brightness of the image displayed in the direction in which the first region 11s1 is viewed in front and the direction in which the second region 11s2 is viewed in front are displayed. The uneven surface 11s is configured so that the brightness of the image is substantially equal to each other.

  Therefore, in the direction in which the display 10 is viewed from the front, the image displayed by the display 10 is visually recognized as one image, and the display 10 is diffracted in the first region 11s1 with respect to the direction in which the display 10 is viewed from the front. An image formed based on the difference between the luminance of light and the luminance of diffracted light in the second region 11s2 can be hidden from the observer.

  As shown in FIG. 9, the first region 11s1 is divided into a plurality of pixels 30, and each pixel 30 has a square shape when viewed from the Z direction, and the plurality of pixels 30 are respectively formed in the X direction and the Y direction. Are lined up along. That is, the plurality of pixels 30 are arranged in a square lattice.

  When viewed from the Z direction, the length of one side of the pixel 30 is the maximum width Wp, and the maximum width Wp is 3 μm or more and 300 μm or less. Since the maximum width Wp is equal to or less than 300 μm, each pixel 30 can be prevented from being visually recognized by an observer when the display body 10 is visually recognized by the naked eye. In addition, since the maximum width Wp is 3 μm or more, the density of the convex and concave surfaces and the accuracy of the shape of the concave and convex surfaces in the concave and convex surfaces included in each pixel 30 are each described as a diffraction grating. And the function of suppressing light reflection can be sufficiently increased.

  Each pixel 30 may have a circular shape when viewed from the Z direction, or may have a polygonal shape other than a square shape, for example, a triangular shape, or a square shape other than a square shape. . Even when each pixel 30 has such a shape, the maximum width of the pixel 30, that is, the longest side among the sides that partition the pixel 30 is preferably 3 μm or more and 300 μm or less.

  Each pixel 30 is a part of the uneven surface 11s and includes a plurality of convex surfaces. That is, each pixel 30 also includes a plurality of concave surfaces, and in each pixel 30, the convex surface and the concave surface are alternately arranged.

  The plurality of pixels 30 configuring the first region 11s1 include a first pixel 31, a second pixel 32, and a third pixel 33. Between the first pixel 31, the second pixel 32, and the third pixel 33, in the direction in which the convex surface extends, and in the period d, that is, in the direction in which the convex surface and the concave surface are repeated in the repeating unit forming the uneven surface. At least one of the lengths is different from each other.

The plurality of pixels 30 forming the first region 11s1 include a first pixel 31, a second pixel 32, and a third pixel 33 at a ratio represented by the following equation (3).
[First pixel]: [Second pixel]: [Third pixel] = 2: 1: 1 (3)

  Although the entirety of each pixel 30 is formed of an uneven surface in which convex surfaces and convex surfaces are alternately arranged, a part of each pixel 30 may include a flat surface. Note that, even if a configuration in which a flat surface is included in a part of each pixel 30 is used, the sum of the areas of the uneven surfaces included in the first pixels 31, the sum of the areas of the uneven surfaces included in the second pixels 32, Further, the ratio of the sum of the areas of the concave and convex surfaces included in each third pixel 33 only needs to satisfy the relationship shown in Expression 3 between the three pixels.

  As shown in FIG. 10, the second region 11s2 is divided into a plurality of pixels 30 similarly to the first region 11s1, and each pixel 30 has a square shape when viewed from the Z direction. They are arranged along each of the X direction and the Y direction. That is, the plurality of pixels 30 are arranged in a square lattice.

  When viewed from the Z direction, the maximum width Wp of the pixel 30 is 3 μm or more and 300 μm or less, like the first region 11s1. Note that, like the first region 11s1, each pixel 30 may have a circular shape or a polygonal shape other than a square shape when viewed from the Z direction.

  Each pixel 30 is a part of the uneven surface 11s and includes a plurality of convex surfaces. That is, each pixel 30 also includes a plurality of concave surfaces, and in each pixel 30, the convex surface and the concave surface are alternately arranged.

  The plurality of pixels 30 forming the second region 11s2 include a first pixel 31, a third pixel 33, and a fourth pixel 34. The first pixel 31 has the same configuration as the first pixel 31 included in the first region 11s1, and the third pixel 33 has the same configuration as the third pixel 33 included in the first region 11s1.

  The fourth pixel 34 is different from the first pixel 31, the second pixel 32, and the third pixel 33 in at least one of the direction in which the convex surface extends and the period d.

The plurality of pixels 30 forming the second region 11s2 include a first pixel 31, a third pixel 33, and a fourth pixel 34 at a ratio represented by the following equation (4).
[1st pixel]: [3rd pixel]: [4th pixel] = 1: 2: 1 ... Equation (4)

  Although the entirety of each pixel 30 is formed of an uneven surface in which convex surfaces and concave surfaces are alternately arranged, a flat surface may be included in a part of each pixel 30. Note that, even if a configuration in which a flat surface is included in a part of each pixel 30 is used, the sum of the areas of the uneven surfaces included in each first pixel 31, the sum of the areas of the uneven surfaces included in each third pixel 33, In addition, the ratio in the sum of the areas of the concave and convex surfaces included in each fourth pixel 34 may satisfy the relationship shown in Expression 4 among the three pixels.

  As shown in FIG. 11, the first pixel 31 which is an example of the first array pixel and the first periodic pixel has a first uneven surface 31s which forms a part of the uneven surface 11s. In the uneven surface 31s, the first convex surfaces 31a and the first concave surfaces 31b are alternately repeated one by one along the Y direction which is an example of the first arrangement direction. Each first convex surface 31a extends along the X direction, which is an example of the first extending direction, and each first concave surface 31b also extends along the X direction.

  Each first convex surface 31a has a first top 31c, and the plurality of first tops 31c are arranged with a first pitch P1 in the Y direction. In the first uneven surface 31s, the first convex surface 31a and the first concave surface 31b adjacent in the Y direction constitute a repeating unit, and the length of the repeating unit along the Y direction is the first period d1. In each of the first uneven surfaces 31s, the above-described maximum width is the first maximum width W1, and the first maximum width W1 is equal to the first cycle d1. The first cycle d1 is a predetermined value included in the range of 200 nm or more and 500 nm or less, like the cycle d described above, and is preferably 400 nm or less. In the first uneven surface 31s, the distance between the first top 31c of the first convex surface 31a and the first bottom 31d of the first concave surface 31b is a first height H1.

  In the first pixel 31, the plurality of first convex surfaces 31a extend along the X direction. Therefore, the first pixel 31 is a fixed point that is a predetermined point on the observation side, and is directed toward the first fixed point included in the YZ plane. To emit diffracted light. The wavelength of the diffracted light emitted from the first pixel 31 toward the first fixed point is a wavelength according to the first period d1.

  As shown in FIG. 12, the second pixel 32, which is an example of a first array pixel and an example of a second periodic pixel, has a second uneven surface 32s forming a part of the uneven surface 11s. In the uneven surface 32s, the second convex surface 32a and the second concave surface 32b are alternately repeated one by one along the Y direction. Each second convex surface 32a extends along the X direction, and each second concave surface 32b also extends along the X direction.

  The second convex surface 32a extends in a strip shape along the X direction, has a shape that tapers toward the second top portion 32c in the Z direction, and the second concave surface 32b extends in a strip shape along the X direction. , And has a shape that tapers toward the second bottom portion 32d along the Z direction.

  Also in the second pixel 32, similarly to the first pixel 31, the light incident on the second pixel 32 is prevented from being reflected in the front view direction of the second pixel 32, and The second convex surface 32a and the second concave surface 32b are arranged in a cycle in which incident light is emitted from the second pixel 32 as diffracted light in a direction oblique to the second pixel 32.

  Each second convex surface 32a has a second top 32c, and the plurality of second tops 32c are arranged with a second pitch P2 in the Y direction. In the second uneven surface 32s, the second convex surface 32a and the second concave surface 32b adjacent in the Y direction constitute a repeating unit, and the length of the repeating unit along the Y direction is a second period d2. The maximum width of each second uneven surface 32s is the second maximum width W2, and the second maximum width W2 is equal to the second period d2. The second period d2 is smaller than the first period d1, is a predetermined value included in the range of 200 nm or more and 500 nm or less, and is preferably 400 nm or less.

  In the second uneven surface 32s, the distance between the second top 32c of the second convex surface 32a and the second bottom 32d of the second concave surface 32b is a second height H2, and the second height H2 is the first height H2. Equal to height H1.

  In the second pixel 32, since the plurality of second convex surfaces 32a extend along the X direction, the second pixel 32 can emit the diffracted light toward the first fixed point similarly to the first pixel 31. However, since the second cycle d2 of the second pixel 32 is different from the first cycle d1 of the first pixel 31, the wavelength of the diffracted light emitted from the second pixel 32 toward the first fixed point, that is, the color of the diffracted light Is different from the wavelength of the diffracted light emitted from the first pixel 31 toward the first fixed point, that is, the color of the diffracted light.

  As shown in FIG. 13, the third pixel 33, which is an example of the second array pixel and the first periodic pixel, has a third uneven surface 33s that forms a part of the uneven surface 11s. In the uneven surface 33s, the third convex surfaces 33a and the third concave surfaces 33b are alternately repeated one by one along the X direction which is an example of the second arrangement direction. Each third convex surface 33a extends along the Y direction which is an example of the second extending direction, and each third concave surface 33b also extends along the Y direction.

  The third convex surface 33a has a shape extending in a belt shape along the Y direction, has a shape tapering along the Z direction toward the third top portion 33c, and the third concave surface 33b has a belt shape extending in the Y direction. , And has a shape that tapers toward the third bottom portion 33d along the Z direction.

  Also in the third pixel 33, similarly to the first pixel 31, it is possible to prevent the light incident on the third pixel 33 from being reflected in the front view direction of the third pixel 33, and The third convex surface 33a and the third concave surface 33b are arranged in a cycle in which incident light is emitted from the third pixel 33 as diffracted light in a direction oblique to the third pixel 33.

  Each third convex surface 33a has a third top 33c, and the plurality of third tops 33c are arranged with a third pitch P3 in the X direction. In the third uneven surface 33s, the third convex surface 33a and the third concave surface 33b adjacent in the X direction constitute a repeating unit, and the length of the repeating unit along the X direction is a third period d3. The maximum width of each of the third uneven surfaces 33s is the third maximum width W3, and the third maximum width W3 is equal to the third period d3. The third cycle d3 is equal to the first cycle d1.

  In the third uneven surface 33s, the distance between the third top 33c of the third convex surface 33a and the third bottom 33d of the third concave surface 33b is a third height H3, and the third height H3 is the first height H3. Equal to height H1.

  In the third pixel 33, since the plurality of third convex surfaces 33a extend along the Y direction, the third pixel 33 is different from each of the first pixel 31 and the second pixel 32 in that the position on the observation side is the first fixed point. And diffracted light can be emitted toward a second fixed point included in the XZ plane. On the other hand, the third cycle d3 of the third pixel 33 is equal to the first cycle d1.

  Here, when the third pixel 33 is observed from the second fixed point, the relative position of the third pixel 33 with respect to the second fixed point is the third pixel position, and the relative position of the light source with respect to the second fixed point is the third light source position. is there. When the first pixel 31 is observed from the first fixed point, the relative position of the first pixel 31 with respect to the first fixed point is the first pixel position, and the relative position of the light source with respect to the first fixed point is the first light source position. . If the third pixel position and the first pixel position are equal to each other and the third light source position and the first light source position are equal to each other, the third pixel 33 moves the first pixel 31 toward the first fixed point. Diffracted light having the same wavelength as the emitted diffracted light, that is, diffracted light having the same color, can be emitted toward the second fixed point.

  As shown in FIG. 14, an example of the second array pixel and a fourth pixel 34 which is an example of the second periodic pixel have a fourth uneven surface 34 s that constitutes a part of the uneven surface 11 s. In the uneven surface 34s, the fourth convex surface 34a and the fourth concave surface 34b are alternately repeated one by one along the X direction. Each fourth convex surface 34a extends along the Y direction, and each fourth concave surface 34b also extends along the Y direction.

  Like the third convex surface 33a, the fourth convex surface 34a has a shape extending in a band along the Y direction and tapering toward the fourth top portion 34c along the Z direction. Similarly to the third concave surface 33b, the fourth concave surface 34b has a shape extending in a band along the Y direction and tapering toward the fourth bottom portion 34d along the Z direction.

  Also in the fourth pixel 34, similarly to the first pixel 31, it is possible to prevent the light incident on the fourth pixel 34 from being reflected in the front view direction of the fourth pixel 34, and The fourth convex surface 34a and the fourth concave surface 34b are arranged in a cycle in which the incident light is emitted from the fourth pixel 34 as diffracted light in a direction oblique to the fourth pixel 34.

  Each fourth convex surface 34a has a fourth top 34c, and the plurality of fourth tops 34c are arranged with a fourth pitch P4 in the X direction. In the fourth uneven surface 34s, the fourth convex surface 34a and the fourth concave surface 34b adjacent in the X direction constitute a repeating unit, and the length of the repeating unit along the X direction is a fourth period d4. The maximum width of each fourth uneven surface 34s is the fourth maximum width W4, and the fourth maximum width W4 is equal to the fourth period d4. The fourth cycle d4 is equal to the second cycle d2.

  In the fourth uneven surface 34s, the distance between the fourth top 34c of the fourth convex surface 34a and the fourth bottom 34d of the fourth concave surface 34b is a fourth height H4, and the fourth height H4 is the first height H4. Equal to height H1.

  In the fourth pixel 34, since the plurality of fourth convex surfaces 34a extend along the Y direction, the fourth pixel 34 can emit the diffracted light toward the second fixed point, similarly to the third pixel 33. On the other hand, the fourth cycle d4 of the fourth pixel 34 is equal to the second cycle d2.

  Here, when the fourth pixel 34 is observed from the second fixed point, the relative position of the fourth pixel 34 with respect to the second fixed point is the fourth pixel position, and the relative position of the light source with respect to the second fixed point is the fourth light source position. is there. When the second pixel 32 is observed from the first fixed point, the relative position of the second pixel 32 with respect to the first fixed point is the second pixel position, and the relative position of the light source with respect to the first fixed point is the second light source position. . If the fourth pixel position and the second pixel position are equal to each other and the fourth light source position and the second light source position are equal to each other, the fourth pixel 34 moves the second pixel 32 toward the first fixed point. Diffracted light having the same wavelength as the emitted diffracted light, that is, diffracted light having the same color, can be emitted toward the second fixed point.

[Function of display body]
The operation of the display 10 will be described with reference to FIGS. FIG. 15 schematically shows an image formed by the diffracted light emitted from the display 10 toward the first fixed point, and FIG. 16 shows an image formed by the diffracted light emitted from the display 10 toward the second fixed point. FIG. FIG. 17 schematically shows an image displayed by the display body 10 in the front view direction.

As shown in FIG. 15, when the light source LS irradiates the illumination light IL from a diagonal direction toward the display body 10 at a predetermined position included in the YZ plane YZ, the observer moves the light source LS included in the YZ plane YZ. It is observed from one fixed point OB1, which is on the opposite side to the emission light RL with respect to the front view direction DLV of the display body 10.
At this time, only the first pixel 31 and the second pixel 32 emit the diffracted light DL toward the first fixed point OB1.

  Here, as described above, the first region 11s1 includes the first pixel 31 and the second pixel 32 as the pixel 30 having the convex surface extending along the X direction, and has the convex surface extending along the Y direction. A third pixel 33 is included as the pixel 30. Therefore, in the first region 11s1, the ratio of the pixel 30 having the convex surface extending along the X direction to the pixel 30 having the convex surface extending along the Y direction is 3: 1.

  On the other hand, the second region 11s2 includes a first pixel 31 as a pixel 30 having a convex surface extending along the X direction, and a third pixel 33 and a fourth pixel 34 as pixels having a convex surface extending along the Y direction. And are included. Therefore, in the second region 11s2, the ratio of the pixel 30 having the convex surface extending along the X direction to the pixel 30 having the convex surface extending along the Y direction is 1: 3.

  That is, between the first region 11s1 and the second region 11s2, the ratio of the sum of the area of each first array pixel to the area of each region and the sum of the area of each second array pixel to the area of each region. The ratios are different from each other.

  Therefore, the luminance of the diffracted light DL emitted from the first region 11s1 toward the first fixed point OB1 is higher than the luminance of the diffracted light DL emitted from the second region 11s2 toward the first fixed point OB1.

  The first region 11s1 includes the first pixel 31 and the second pixel 32 as the pixels 30 that can emit the diffracted light DL toward the first fixed point OB1, while the second region 11s2 includes the first pixel 31 and the second pixel 32. Includes only the first pixel 31. That is, the ratio between the sum of the areas of the first pixels 31 and the sum of the areas of the second pixels 32 is different between the first region 11s1 and the second region 11s2.

  Therefore, the diffracted lights DL emitted from the first region 11s1 toward the first fixed point OB1 are two diffracted lights DL having different wavelengths, and the images displayed by the first region 11s1 are two different images. The image is visually recognized as a first color image that is a mixed color.

  On the other hand, the diffracted light DL emitted from the second region 11s2 toward the first fixed point OB1 has the same wavelength as one of the two diffracted lights DL emitted from the first region 11s1 toward the first fixed point OB1. Is the diffracted light DL having Therefore, the image displayed in the second area 11s2 is visually recognized as an image having a second color different from the first area 11s1.

  That is, the color of the diffracted light DL emitted from the first region 11s1 toward the first fixed point OB1 is different from the color of the diffracted light DL emitted from the second region 11s2 toward the first fixed point OB1. , An uneven surface 11s. The color of the diffracted light DL is a second characteristic, and the second characteristic is included in the characteristic of the diffracted light DL.

  As described above, since the first region 11s1 and the second region 11s2 can display images having different luminances and colors toward the first fixed point OB1, the image displayed by the first region 11s1 and the second region 11s2 can be displayed. The image displayed by 11s2 is visually separated at the first fixed point OB1. In addition, since the color of light emitted from the first region 11s1 and the color of light emitted from the second region 11s2 are different from each other, only the brightness differs between the light emitted from each of the two regions. In comparison, the first region 11s1 and the second region 11s2 are more clearly divided.

As shown in FIG. 16, when the light source LS irradiates the illumination light IL obliquely toward the display 10 at a predetermined position included in the XZ plane XZ, the observer includes the illumination light IL in the XZ plane XZ. The second fixed point OB2 is observed from the side opposite to the emission light RL with respect to the front view direction DLV of the display body 10.
At this time, only the third pixel 33 and the fourth pixel 34 emit the diffracted light DL toward the second fixed point OB2.

  Therefore, the luminance of the diffracted light DL emitted from the second region 11s2 toward the second fixed point OB2 is higher than the luminance of the diffracted light DL emitted from the first region 11s1 toward the second fixed point OB2.

  Further, as the pixel 30 that can emit the diffracted light DL toward the second fixed point OB2, only the third pixel 33 is included in the first region 11s1, while the third pixel 33 is included in the second region 11s2. And the fourth pixel 34. That is, the ratio between the sum of the areas of the third pixels 33 and the sum of the areas of the fourth pixels 34 is different between the first region 11s1 and the second region 11s2.

  Therefore, the diffracted lights DL emitted from the second area 11s2 toward the second fixed point OB2 are two diffracted lights DL having different wavelengths, and the images displayed by the second area 11s2 are two different images. It is visually recognized as an image of a mixed color. The color of the image displayed by the second area 11s2 is the same first color as the color of the image displayed by the first area 11s1 when the first area 11s1 is viewed from the first fixed point OB1.

  On the other hand, the diffracted light DL emitted from the first area 11s1 toward the second fixed point OB2 has the same wavelength as one of the two diffracted lights DL emitted from the second area 11s2 toward the second fixed point OB2. Is the diffracted light DL having Therefore, the image displayed in the first region 11s1 is visually recognized as an image having a different color from the image displayed in the second region 11s2. The color of the image displayed in the first area 11s1 is the same second color as the color of the image displayed in the second area 11s2 when the second area 11s2 is viewed from the first fixed point OB1.

  As described above, since the first region 11s1 and the second region 11s2 can display images having different luminances and colors toward the second fixed point OB2, the image displayed by the first region 11s1 and the second region 11s2 can be displayed. The image displayed by 11s2 is visually separated at the second fixed point OB2.

  Further, according to the display 10, the observation point of the display 10 changes between the first fixed point OB1 and the second fixed point OB2, so that the diffracted light DL between the first region 11s1 and the second region 11s2. The magnitude of the luminance of the image can be reversed. That is, the display 10 can display an image at the second fixed point OB2 in which the relationship between the luminance of the first area 11s1 and the luminance of the second area 11s2 is reversed from the image displayed toward the first fixed point OB1. it can.

  Further, according to the display body 10, the observation point of the display body 10 is changed between the first fixed point OB1 and the second fixed point OB2, so that the diffracted light between the first area 11s1 and the second area 11s2 is formed. The colors can be reversed between a first color and a second color.

  On the other hand, as shown in FIG. 17, the display body 10 displays an image with reduced brightness, for example, an image having black, toward the third fixed point OB3 which is a predetermined point in the front view direction DLV. .

  Here, the first height H1 of the first uneven surface 31s, the second height H2 of the second uneven surface 32s, the third height H3 of the third uneven surface 33s, and the fourth height of the fourth uneven surface 34s. H4 are equal to each other. Therefore, a difference in the brightness of the image displayed by each pixel 30 in the front view direction DLV due to the difference in the height of the uneven surface for each pixel 30 is suppressed.

  Further, as described above, in the first region 11s1, the pixel 30 whose period d on the concave-convex surface is the first period d1 or the third period d3 and the pixel 30 whose period d on the concave-convex surface is the second period d2 are The ratio is 3: 1.

  On the other hand, in the second region 11s2, the ratio of the pixel 30 whose period d on the uneven surface is the first period d1 or the third period d3 to the pixel 30 whose period d on the uneven surface is the fourth period d4 is 3 : 1.

  As described above, the size of each pixel 30 is so small that each pixel 30 cannot be distinguished when the display 10 is observed with the naked eye. Therefore, in each of the first region 11s1 and the second region 11s2, the brightness in the first region 11s1 and each of the brightness in the second region 11s2 are visually recognized as the average value of the brightness in each pixel 30 included in each region. You.

  Moreover, between the first region 11s1 and the second region 11s2, the pixel 30 whose period d is the first period d1 or the third period d3 and the pixel 30 whose period d is the second period d2 or the fourth period d4 Are equal to each other, the brightness of the image displayed by the first region 11s1 and the brightness of the image displayed by the second region 11s2 are equal to each other.

  Thus, when the display 10 is viewed from the third fixed point OB3, the image displayed by the display 10 is viewed as one image. As a result, when the display 10 is viewed from the front view direction DLV, the image formed by the display 10 by the first region 11s1 and the second region 11s2 is hidden from the observer.

[Layer structure of display body]
With reference to FIGS. 18 and 19, a configuration that can be adopted as the above-described display body 10, that is, the display body 10 of the first embodiment and the second embodiment will be described. In FIGS. 18 and 19, for convenience of description, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment.

  As shown in FIG. 18, an example of the display body 10 includes an uneven structure layer 41 that is an example of the uneven structure, and a metal layer 42 that covers the uneven surface 11 s among the surfaces of the uneven structure layer 41. . That is, the laminate of the uneven structure layer 41 and the metal layer 42 forms an example of the uneven structure. In the display 10, of the surfaces of the uneven structure layer 41, the surface opposite to the surface in contact with the metal layer 42 is a flat surface, and the flat surface is the front surface of the display 10. The surface of the metal layer 42 opposite to the surface in contact with the uneven structure layer 41 is the back surface of the display body 10.

  In such a display 10, the surface of the metal layer 42 that is in contact with the uneven surface 11s, which is an example of the transmission-side uneven surface, is also an example of the uneven surface 42s, which is the light incident surface. Of the uneven surface 42s of the metal layer 42, a portion in contact with the convex surface 11a of the uneven layer 41 is the convex surface 42a of the metal layer 42, and a portion in contact with the concave surface 11b of the uneven layer 41 is a concave surface 42b in the metal layer 42. Further, of the uneven surface 42s of the metal layer 42, a portion in contact with the top 11c of the uneven structure layer 41 is a top 42c of the metal layer 42, and a portion in contact with the bottom 11d of the uneven structure layer 41 is a bottom 42d of the metal layer 42. is there.

  When light is incident from the front surface of the display body 10, the interface between the concave-convex structure layer 41 and the metal layer 42, that is, each of the concave-convex structure layer 41 and the metal layer 42 has a convex surface and a concave surface with a period that suppresses light reflection. Are arranged, so that reflection at the interface is suppressed and light passes through the metal layer 42. Then, the light that has entered the inside of the metal layer 42 is absorbed by the metal layer 42, that is, converted into heat energy inside the metal layer 42.

  On the other hand, the interface between the concavo-convex structure layer 41 and the metal layer 42, that is, each of the concavo-convex structure layer 41 and the metal layer 42 has a convex surface 42a and a concave surface 42b with a period of emitting diffracted light in a direction oblique to the display body 10. And the uneven surface 11 s of the uneven structure layer 41 is in contact with the metal layer 42. Accordingly, the light reflectance on the uneven surface 11s is increased, so that diffracted light is easily emitted from the uneven surface 11s.

  If the display body 10 includes the uneven structure layer 41 and the metal layer 42, the uneven surface 11 s of the uneven structure layer 41 is not exposed to the outside of the display body 10. In comparison, the uneven surface 11s is less likely to be damaged. Therefore, the display 10 can display an image with higher visibility.

  The uneven structure layer 41 is a layer having light transmittance, and the uneven structure layer 41 may be formed of a transparent material. The uneven structure layer 41 includes, for example, a step of applying a resin on a plate-shaped member to form a coating film, and a step of curing the resin forming the coating film while pressing a stamper against the coating film. Formed by Alternatively, the concavo-convex structure layer 41 is formed by a step of applying a resin to an intaglio for forming the concavo-convex structure layer 41 and a step of curing the applied resin. The forming material of the uneven structure layer 41 is, for example, a thermoplastic resin, a thermosetting resin, a photocurable resin, or the like.

The material for forming the metal layer 42 is, for example, aluminum, silver, gold, or an alloy of these metals. The metal layer 42 is formed so as to cover the uneven surface 11s by, for example, a vapor deposition method such as a vacuum evaporation method and a sputtering method. The metal layer 42 has a property of absorbing light incident on the uneven structure.
When the display body 10 is formed, for example, the metal layer 42 may be formed so as to cover the uneven surface 11s of the uneven structure layer 41 after the uneven structure layer 41 is formed.

  Alternatively, if the metal layer 42 is configured to include an uneven surface that functions as a relief of the uneven structure layer 41 and a flat surface opposite to the uneven surface, the display body 10 is formed by the following method. You can also. That is, the metal layer formed by the above-described vapor deposition method is physically or chemically etched to form the metal layer 42, and the uneven structure layer 41 is formed on the uneven surface 42 s of the metal layer 42. The display body 10 can also be formed by applying a forming resin.

  In the display 10, of the surfaces of the uneven structure layer 41, the surface opposite to the surface in contact with the metal layer 42 is the back surface of the display 10 and the uneven structure of the metal layer 42. The surface opposite to the surface in contact with the layer 41 may be the front surface of the display 10. In such a configuration, the uneven surface as the light incident surface of the display body 10 is the surface of the metal layer 42 opposite to the surface in contact with the uneven structure layer 41, and the metal layer 42 and the uneven structure layer 41 It constitutes an example of a structure.

  That is, the display 10 includes an uneven structure including the uneven structure layer 41 and the metal layer 42. The concavo-convex structure layer 41 has a concavo-convex surface 11s which is an example of the transmission-side concavo-convex surface. The metal layer 42 covers the uneven surface 11s, has a surface in contact with the uneven surface 11s, and a surface opposite to the surface in contact with the uneven surface 11s, and one of these two surfaces receives light. It is an uneven surface as an incident surface.

  Each convex surface extends in a strip shape along the extending direction orthogonal to the above-described arrangement direction, and has a shape that tapers toward the top along the thickness direction of the uneven structure. Further, each concave surface has a shape extending in a belt shape along the extending direction, and tapering toward the bottom along the thickness direction of the uneven structure. The uneven surface suppresses the light incident on the uneven surface from being reflected in a direction in which the uneven surface is viewed from the front, and diffracts the light incident on the uneven surface in a direction oblique to the uneven surface. The convex surface and the concave surface are arranged in a cycle of emitting light from the uneven surface as light.

  As shown in FIG. 19, one example of the display body 10 is a laminate of a light transmission layer 40 and a metal layer 42. In the display 10, the surface of the light transmission layer 40 opposite to the surface in contact with the metal layer 42 is the front surface, and the surface of the metal layer 42 opposite to the light transmission layer 40 is the back surface.

  The light transmission layer 40 is a laminate composed of the support layer 43 and the uneven structure layer 41, and the uneven structure layer 41 is sandwiched between the support layer 43 and the metal layer 42. In the uneven structure layer 41, the surface in contact with the metal layer 42 is the uneven surface 11s as a light incident surface.

  That is, a laminate of the uneven structure layer 41 and the metal layer 42 is an example of the uneven structure. Then, similarly to the display 10 described above with reference to FIG. 18, the surface of the metal layer 42 that is in contact with the uneven surface 11s is also an example of the uneven surface 42s that is the light incident surface. Of the uneven surface 42s of the metal layer 42, a portion in contact with the convex surface 11a of the uneven layer 41 is the convex surface 42a of the metal layer 42, and a portion in contact with the concave surface 11b of the uneven layer 41 is a concave surface 42b in the metal layer 42. Further, of the uneven surface 42s of the metal layer 42, a portion in contact with the top 11c of the uneven structure layer 41 is a top 42c of the metal layer 42, and a portion in contact with the bottom 11d of the uneven structure layer 41 is a bottom 42d of the metal layer 42. is there.

  The light transmission layer 40 may have a multilayer structure of three or more layers including other layers in addition to the support layer 43 and the uneven structure layer 41. In this case, the other layer may be located, for example, between the support layer 43 and the uneven structure layer 41 or on the surface of the support layer 43 opposite to the uneven structure layer 41.

  The support layer 43 is a film or sheet that can be handled alone. The material for forming the support layer 43 is a resin having a light transmitting property, such as polycarbonate and polyester.

  The uneven structure layer 41 is formed by, for example, a step of applying a resin on the support layer 43 to form a coating film, and a step of curing the resin forming the coating film while pressing a stamper against the coating film. Is done. The formation material of the uneven structure layer 41 is, for example, a thermoplastic resin, a thermosetting resin, a photocurable resin, or the like, like the uneven structure layer 41 described above with reference to FIG.

  Although the metal layer 42 is formed on the entire uneven surface 11s of the uneven structure layer 41, the metal layer 42 may be formed only on a part of the uneven surface 11s of the uneven structure layer 41. Note that these items similarly apply to the configuration described above with reference to FIG. 18.

  The material for forming the metal layer 42 is, for example, any of the above-mentioned metals and alloys. Since the uneven surface 11s of the uneven structure layer 41 is in contact with the metal layer 42, the light reflectance on the uneven surface 11s is increased, and diffracted light is easily emitted from the uneven surface 11s.

  The metal layer 42 is formed by, for example, a vapor deposition method such as a vacuum evaporation method and a sputtering method. In a configuration in which the metal layer 42 is formed on a part of the uneven surface 11s, the metal layer 42 is formed by the following method.

  That is, the metal layer 42 is formed by a process of forming a metal thin film on the entire uneven surface 11 s of the uneven structure layer 41 using a vapor deposition method and a process of patterning the thin film. In the step of patterning the thin film, a method of dissolving a part of the thin film with a chemical such as alkali or acid, or using an adhesive material having an adhesive force to the thin film stronger than the adhesive force between the thin film and the uneven structure layer 41 is used. Then, a method of removing a part of the thin film can be used. Further, the metal layer 42 located on a part of the uneven surface 11s can also be formed by a vapor deposition method using a mask.

In the light transmitting layer 40, the surface opposite to the surface in contact with the metal layer 42 is the back surface, and the surface of the metal layer 42 opposite to the surface in contact with the uneven structure layer 41 is the front surface. There may be. In such a configuration, the uneven surface as the light incident surface in the display body 10 is the surface of the metal layer 42 opposite to the surface in contact with the uneven structure layer 41, and the metal layer 42 and the uneven structure layer 41 This constitutes an example of the uneven structure.
The display body 10 may further include other layers such as an adhesive layer, an adhesive layer, and a resin layer, in addition to the light transmitting layer 40 and the metal layer 42 described above.

  In the configuration in which the display body 10 includes at least one of the adhesive layer and the adhesive layer, the adhesive layer and the adhesive layer may be, for example, a layer that covers the surface of the metal layer 42 opposite to the uneven structure layer 41. Any layer that forms the back surface of the display body 10 may be used. In a configuration in which the display body 10 includes the light transmission layer 40 and the metal layer 42, the shape of the back surface formed by the metal layer 42 is generally substantially equal to the shape of the interface between the uneven structure layer 41 and the metal layer 42. If at least one of the adhesive layer and the adhesive layer forms a back surface of the display 10, the surface of the metal layer 42 can be prevented from being exposed to the outside of the display 10.

  In addition, the surface of at least one of the adhesive layer and the adhesive layer, and the shape of the back surface of the display body 10 is a shape obtained by smoothing the shape of the surface of the metal layer 42. It has a shape different from itself. Therefore, duplication of the display 10 for the purpose of forgery can be made difficult.

  In the display body 10, when the surface of the light transmitting layer 40 opposite to the metal layer 42 is the back surface, and the surface of the metal layer 42 opposite to the light transmitting layer 40 is the front surface, the adhesive layer At least one of the adhesive layer and the adhesive layer may be formed on the surface of the light transmitting layer 40 opposite to the surface in contact with the metal layer 42. When the surface of the metal layer 42 opposite to the light transmission layer 40 is the front surface and the uneven surface as the incident surface, the display body 10 is located on the back side of the metal layer 42 in the display 10. The light-shielding layer may be located in addition to or instead of the light-transmitting layer 40.

  The resin layer that can be provided in the display body 10 may be, for example, positioned as a layer that forms the front surface of the display body 10 with respect to the laminate of the light transmission layer 40 and the metal layer 42. For example, when the metal layer 42 is located on the front side with respect to the light transmission layer 40, the metal layer 42 is covered with the resin layer, so that damage to the metal layer 42 is suppressed. In addition, since the metal layer 42 is covered with the resin layer, duplication of the metal layer 42 for the purpose of forgery can be made difficult.

  The resin layer includes, for example, a hard coat layer for preventing the front surface of the display body 10 from being damaged, an antifouling layer for preventing the display body 10 from being stained, and reflection of light on the front surface of the display body 10. And an anti-reflection layer for preventing charging of the display 10.

  The display 10 may further include a print layer, and the print layer may be located on the light transmission layer 40 side with respect to the metal layer 42. That is, the printing layer may be located on the surface of the support layer 43 opposite to the surface in contact with the uneven structure layer 41, or may be located between the support layer 43 and the uneven structure layer 41. Alternatively, it may be located between the uneven structure layer 41 and the metal layer 42.

  According to the configuration in which the display body 10 includes the print layer, the information that the display body 10 can display is added by the print layer, so that the display body 10 can display a more complicated image. Further, according to the print layer, it is easier to add information to the display 10 as compared with a configuration in which information is added to the display 10 by an uneven surface.

[Method of manufacturing display body]
An example of a method for manufacturing the display body 10 will be described with reference to FIGS. Hereinafter, a method of manufacturing an original plate for forming the uneven surface 11s provided in the display body 10 among the manufacturing methods of the display body 10 will be described.

  In addition, as an example of the method of manufacturing the original plate, two methods for forming the uneven surface 11s in which the distance between the top and the bottom of the uneven surface 11s is 450 nm and the pitch at which the tops are arranged are 400 nm. Will be described. When manufacturing an original plate, one resin layer formed of polymethyl acrylate, which is a positive resist, is prepared, and the resin layer is irradiated with an electron beam. In a resin layer formed from a positive resist, the amount of dissolution in a portion irradiated with an electron beam is larger than the amount of dissolution in a portion not irradiated with electrons. Therefore, after the resin layer is developed, the portion of the resin layer that has been irradiated with the electron beam is more dented than the portion of the resin layer that has not been irradiated with the electron beam with respect to the surface of the resin layer that has been irradiated with the electron beam. .

FIG. 20 shows the relationship between the irradiation amount (μC / cm ² ) of the electron beam to polymethyl acrylate, which is the material for forming the master, and the amount of polymethyl acrylate dissolved. The weight average molecular weight of polymethyl acrylate is 495,000, and the dissolution amount of polymethyl acrylate is determined by immersing polymethyl acrylate after irradiation in a developer, 4-methyl-2-pentanone, for 12 minutes. Is the amount of dissolution.

As shown in FIG. 20, when the polymethyl acrylate is not irradiated with an electron beam, that is, when the irradiation amount of the electron beam is 0 μC / cm ² , the dissolution amount of the polymethyl acrylate is 100 nm.

Therefore, in order to set the distance between the top and the bottom to 450 nm, the irradiation amount of the electron beam should be such that the amount of dissolution in the thickness direction of the resin layer becomes 550 nm and about 35 μC / cm ² . I just need. The resin layer has one irradiation surface, which is one surface, and the electron beam is irradiated on the irradiation surface of the resin layer.

  In the first method, an irradiation part having a width of 100 nm and a non-irradiation part having a width of 300 nm are alternately partitioned along one direction with respect to the irradiation surface of the resin layer, and each irradiation part has an electron beam. A line is illuminated.

  When the irradiated resin layer is immersed in a developing solution and developed, the irradiated surface and the vicinity of the irradiated surface in the resin layer are exposed to the developing solution from the beginning of the phenomenon. Therefore, on the irradiation surface, the irradiation portion and the two regions sandwiching the irradiation portion in one direction and two regions having a width of 100 nm are also dissolved. Thereby, the width of the resin layer dissolved on the irradiation surface is about 300 nm.

On the other hand, in the thickness direction of the resin layer, the longer the distance from the irradiation surface, the shorter the exposure time of the two regions sandwiching the irradiation portion in one direction to the developer. In the resin layer, the portion of the resin layer to be melted, the portion having the largest distance from the irradiation surface in the thickness direction of the resin layer is the deepest portion, and the deepest portion is the portion before the development of the resin layer is completed. It is only exposed to the developer for a short time. Therefore, at the deepest portion, the width in which polymethyl acrylate is dissolved in one direction is approximately equal to the width of the irradiated portion in one direction, and is about 100 nm.
FIG. 21 shows a partial cross-sectional structure of the original plate formed by the first method, which is measured by an atomic force microscope.

  In the measurement conditions of the atomic force microscope, the spring constant of the cantilever was 40.000 N / m, the torsion spring constant was 100.0 N / m, the resonance frequency was 300.00 kHz, and the length of the lever was 140.0 μm. The height of the needle was set to 10.00 μm, and a light lever type atomic force microscope was used. At this time, the excitation voltage was 0.018 V, the resonance frequency was 268.215 kHz, and the measurement frequency was 268.010 kHz. Among the vibration constants at the time of measurement, the amplitude attenuation rate was -0.279, the Q curve gain was 1.50, and the Q value was 463.608.

  As shown in FIG. 21, the original plate 51 has an uneven surface 51s. The uneven surface 51s includes a convex surface 51a corresponding to the convex surface 11a of the uneven structure layer 41 shown in FIG. 18 and a concave surface 51b corresponding to the concave surface 11b of the uneven structure layer 41. The convex surfaces 51a and the concave surfaces 51b are alternately arranged. In FIG. 21, the shape of the uneven surface 51 s is substantially the shape described above from the measurement result of the atomic force microscope, the pitch at which the tops 51 c are arranged is about 400 nm, and the distance between the top 51 c and the bottom 51 d is It was found to be approximately 450 nm.

The second method is different from the first method in that one irradiation unit is irradiated with the electron beam twice, and the irradiation amount of the electron beam irradiated to the irradiation unit at one time is different. different. That is, in the first irradiation of the electron beam, the entire irradiation section was irradiated with the electron beam at a dose of ²⁰ μC / cm ² .

Next, in the second electron beam irradiation, first, a partial irradiation unit is set inside each irradiation unit. The partial irradiation part is a part having a width of 20 nm along one direction and extending along the thickness direction of the resin layer. In one direction, the center of the irradiation part and the center of the partial irradiation part Is a part set to match. Then, in the second electron beam irradiation, the partial irradiation part is irradiated with an electron beam at a dose of ²⁰ μC / cm ² .
FIG. 22 shows a partial cross-sectional structure of an original plate formed by the second method, which is measured by an atomic force microscope.

  As shown in FIG. 22, the original 52 has an uneven surface 52s. The uneven surface 52s includes a convex surface 52a corresponding to the convex surface 11a of the uneven structure layer 41 shown in FIG. 18 and a concave surface 52b corresponding to the concave surface 11b of the uneven structure layer 41. The convex surfaces 52a and the concave surfaces 52b are alternately arranged. In the uneven surface 52s, similarly to the original plate 51 formed by the first method, it was found that the pitch at which the tops 52c were arranged was about 400 nm, and the distance between the tops 52c and the bottoms 52d was about 450 nm. On the other hand, in the original plate 52 formed by the second method, the irradiation amount of the electron beam is larger in a portion where the irradiation unit and the partial irradiation unit overlap than in other portions in the irradiation unit.

  Therefore, the width of the convex surface 52a along the one direction at the top 52c reflects the width of the partial irradiation portion along the one direction, and as a result, the width of the top 52c along the one direction is approximately 20 nm.

  As described above, in the uneven surface, the smaller the area of the flat surface forming the bottom and the smaller the area of the flat surface forming the top are, the smaller the light reflectance at each of the top and bottom is. Therefore, according to the master 52 formed by using the second method, the display body 10 formed by using the master 52 is compared with the master 51 formed by using the first method. The brightness of the image displayed when the image 10 is viewed in the front view direction is reduced.

  It is possible to obtain a stamper on which the uneven surface is transferred by nickel electroforming of the uneven surface of the original obtained by the first method or the second method. Then, for example, an uneven surface made of a resin can be formed by transferring the uneven surface of the stamper to the resin layer. In this case, since each convex surface and each concave surface constituting the concave-convex surface of the stamper have a tapered shape, the concave-convex structure is easily detached from the stamper, and as a result, the productivity of the display body 10 is enhanced.

  Further, according to the second method, since the area of the top is smaller than that of the first method, the uneven surface of the stamper obtained by transferring the original plate easily enters the resin layer. The moldability of the is improved. The improvement of the moldability contributes to the improvement of the molding speed, and as a result, the productivity of the display body can be increased. In addition, the aspect ratio of the uneven surface can be increased by improving the moldability. Therefore, the second method is also effective in lowering the brightness of an image displayed when the display 10 is viewed in a direction in which the display 10 is viewed from the front.

  The material for forming the master is not limited to polymethyl acrylate, but may be an acrylic resin other than polymethyl acrylate, a novolak resin, or a resist material such as hydroxystyrene. Further, the developer is not limited to 4-methyl-2-pentanone, and may be an alkyl acetate, a ketone, an aromatic compound, or a mixture thereof. The aromatic compound is, for example, xylene, anisole, chlorobenzene, or the like.

  When the original material is a novolak resin and a resist material such as polyhydroxystyrene, an ammonium salt such as tetramethylammonium hydroxide and a hydroxide such as potassium hydroxide may be used as a developing solution. it can.

  The method for developing the resin layer, the time for developing the resin layer, and the width of the irradiated portion for irradiating the electron beam can be arbitrarily selected as long as the original having the uneven surface can be formed. is there. In the second method, the irradiation of the irradiation unit with the electron beam is performed next to the irradiation of the partial irradiation unit. However, after the irradiation of the partial irradiation unit with the electron beam, the irradiation of the irradiation unit with the electron beam is performed. May be performed. Further, in the second method, one irradiation unit is irradiated with the electron beam twice, but one irradiation unit may be irradiated with the electron beam three or more times. In this case, a plurality of partial irradiation units are set for the irradiation unit, and in each of the partial irradiation units, the center in the width direction matches the center in the width direction of the irradiation unit, and between each of the partial irradiation units. The widths along one direction may be set to be different from each other.

[Composition of goods]
The display body 10 described above is applied to an article for the purpose of preventing forgery of the article. The display body 10 can suppress the reflection of light in the direction in which the display body 10 is viewed from the front by the uneven surface 11 s of the display body 10, and emits diffracted light in the direction oblique to the display body 10. can do.

  Therefore, it is difficult to forge the display by imitating the shape of the uneven surface 11s of the display 10. Therefore, forgery of the article can be made difficult by attaching the display body 10 to the article.

  It is determined whether or not the display body 10 can suppress the reflection of light in the direction in which the display body 10 is viewed from the front and emit diffracted light in the direction in which the display body 10 is oblique. By performing the verification, it is possible to determine the authenticity of the display body 10 and thus the authenticity of the article.

With reference to FIG. 23 and FIG. 24, a configuration of an IC card as an example of an article provided with the display 10 will be described.
As shown in FIG. 23, an IC (integrated circuit) card 60 is a base material 61 having a plate shape, for example, a base material 61 formed of plastic and a print layer 62 on which a predetermined image is printed. , An IC chip 63, and a display 10.

  As shown in FIG. 24, the printing layer 62 is formed on one surface of the base material 61, and among the surfaces of the printing layer 62, the surface opposite to the surface in contact with the base material 61 has the above-described structure. The display body 10 is fixed using, for example, an adhesive layer. The display body 10 is prepared, for example, as a sticker having an adhesive layer or a transfer foil, and is attached to the print layer 62.

  A concave portion 61a is formed in the base material 61 from a part of the surface in contact with the print layer 62 toward a surface opposite to the surface in contact with the print layer 62. The print layer 62 has a thickness of the IC card 60. In the vertical direction, a through hole 62a is formed at a position overlapping the concave portion 61a. The IC chip 63 is fitted into the concave portion 61a and the through-hole 62a, and the IC chip 63 has a plurality of electrodes on a surface surrounded by the print layer 62. In the IC chip 63, writing of information to the IC chip 63 and reading of information recorded on the IC chip 63 are performed through a plurality of electrodes.

  Since the IC card 60 includes the display body 10 that is difficult to forge, it is difficult to forge the IC card 60. Moreover, since the IC card 60 includes the IC chip 63 and the printing layer 62 in addition to the display body 10, it is also possible to suppress forgery using the IC chip 63 and the printing layer 62.

  As described above, according to the display of the second embodiment, the following effects can be obtained in addition to the effects obtained by the display of the first embodiment.

  (2) For the observer who observes the display body 10 from a fixed point on the observation side, the display body 10 has the luminance of the diffracted light emitted from the first area 11s1 and the intensity of the diffracted light emitted from the second area 11s2. An image formed based on the difference from the luminance can be displayed. Therefore, as compared with a configuration in which one type of diffracted light is emitted from the entire uneven surface 11s, an image displayed in the direction in which the uneven surface 11s is perspective becomes more complicated among images displayed by the uneven surface 11s.

  (3) The display 10 displays an image displayed toward the first fixed point OB1 and an image displayed toward the second fixed point OB2 based on the difference between the luminance of the first area 11s1 and the luminance of the second area 11s2. Can be formed. The display 10 may display an image at the second fixed point OB2 in which the relationship between the luminance of the first area 11s1 and the luminance of the second area 11s2 is reversed from the image displayed toward the first fixed point OB1. it can.

  (4) In the image displayed by the display 10 toward the fixed point, the color of the first region 11s1 and the color of the second region 11s2 are different from each other. The first region 11s1 and the second region 11s2 are more clearly divided.

  (5) In the direction in which the display 10 is viewed from the front, the image displayed by the display 10 is visually recognized as one image. An image formed based on the difference between the characteristic of the diffracted light in 11s1 and the characteristic of the diffracted light in the second region 11s2 can be hidden from the observer.

[Modification of Second Embodiment]
Note that the above-described second embodiment can be implemented with appropriate modifications as described below.
The second arrangement direction may intersect with the first arrangement direction so as to form an angle other than perpendicular. Even with such a configuration, between the first array pixel in which the concave surface and the convex surface are alternately arranged along the first array direction and the second array pixel in which the concave surface and the convex surface are alternately arranged along the second array direction. In, the directions in which diffracted light is emitted can be different from each other.

  The plurality of pixels 30 forming the uneven surface 11s are composed of the first pixel 31, the second pixel 32, the third pixel 33, and the fourth pixel 34, and the uneven surface 11s is formed by the first region 11s1 and the first region 11s1. It does not have to be divided into the two regions 11s2. Even with such a display body, it is possible to emit light having a mixed color of two colors to each of the first fixed point and the second fixed point.

  At the first fixed point OB1, only the first region 11s1 may emit diffracted light, while at the second fixed point OB2, only the second region 11s2 may emit diffracted light. Even with such a configuration, the image displayed in the first region 11s1 and the second image are displayed both when the display body 10 is viewed from the first fixed point OB1 and when the display body 10 is viewed from the second fixed point OB2. The image displayed in the two regions 11s2 is visually separated based on the difference in the luminance of the diffracted light.

  That is, the pixel 30 forming the first region 11s1 is at least one of the first pixel 31 and the second pixel 32, whereas the pixel 30 forming the second region 11s2 is the third pixel 33 and the At least one of the four pixels 34 may be used.

  The luminance of the diffracted light emitted from the first area 11s1 toward the first fixed point OB1 is higher than the luminance of the diffracted light emitted from the second area 11s2 toward the first fixed point OB1, and the first area 11s1 May be higher than the brightness of the diffracted light emitted from the second region 11s2 toward the second fixed point OB2. With such a configuration, the image displayed in the first area 11s1 and the image displayed in the second area 11s2 are displayed both when the display body 10 is viewed from the first fixed point OB1 and when the display body 10 is viewed from the second fixed point OB2. The image is visually distinguished.

For example, the ratio of the area of each third pixel 33 and the sum of the area of each fourth pixel 34 to the area of the first region 11s1 is different from the area of each third pixel 33 and the area of each fourth pixel 34 to the second region 11s2. What is necessary is just to be larger than the ratio with the sum of the areas.
The luminance of the diffracted light emitted from the first region 11s1 toward each fixed point may be lower than the luminance of the diffracted light emitted from the second region 11s2 toward each fixed point.

  The point is that the first region 11s1 includes at least the first arrangement pixels, and the second region 11s2 includes at least the second arrangement pixels. The ratio of the sum of the areas of the first array pixels to the area of the first region 11s1 and the ratio of the sum of the areas of the second array pixels to the area of the second region 11s2 may be different from each other. Furthermore, the ratio of the sum of the areas of the second array pixels to the area of the first region 11s1 and the ratio of the sum of the areas of the second array pixels to the area of the second region 11s2 may be different from each other. According to such a configuration, the following effects can be obtained.

  (6) In each of the image displayed by the display 10 toward the first fixed point OB1 and the image displayed toward the second fixed point OB2, the brightness of the image displayed in the first area 11s1 and the second area 11s2 Are different from each other. Therefore, the display body 10 can display an image in which a portion displayed by the first region 11s1 and a portion displayed by the second region 11s2 are visually separated by a difference in luminance between the two images.

If the plurality of pixels 30 forming the uneven surface 11s include the first array pixels and the second array pixels, the uneven surface 11s is divided into the first region 11s1 and the second region 11s2. It is not necessary.
Even with such a configuration, the effects described below can be obtained.

  (7) Since the uneven surface 11s includes a first array pixel that emits diffracted light toward the first fixed point OB1 and a second array pixel that emits diffracted light toward the second fixed point OB2, the display body 10 An image can be displayed on the first fixed point OB1 and the second fixed point OB2 by diffracted light emitted from different pixels.

  While the color of the diffracted light emitted from the first area 11s1 toward the fixed point and the color of the diffracted light emitted from the second area 11s2 toward the fixed point are different from each other, the color of the diffracted light emitted from the first area 11s1 toward the fixed point is different. The luminance of the emitted diffracted light may be equal to the luminance of the diffracted light emitted from the second region 11s2 toward the fixed point. Even with such a configuration, the image displayed by the first area 11s1 and the image displayed by the second area 11s2 can be visually distinguished.

  For example, the first region 11s1 has one of the first pixel 31 and the second pixel 32 and one of the third pixel 33 and the fourth pixel 34 at a ratio of 1: 1, and the second region 11s2 has , The other of the first pixel 31 and the second pixel 32 and the other of the third pixel 33 and the fourth pixel 34 only have to have 1: 1.

  If the color of the diffracted light emitted from the first area 11s1 toward the first fixed point OB1 and the color of the diffracted light emitted from the second area 11s2 toward the first fixed point OB1 are different from each other, the first The configuration of the plurality of pixels 30 included in the region 11s1 and the configuration of the plurality of pixels 30 included in the second region 11s2 may be different from the configuration in the second embodiment.

  For example, in all of the pixels 30 that are included in the first region 11s1 and emit the diffracted light toward the first fixed point OB1, while the period d is the first period, the period d is included in the second region 11s2, and In all of the pixels 30 that emit the diffracted light toward the first fixed point OB1, the cycle d may be a second cycle different from the first cycle. Even in such a configuration, the color of the diffracted light emitted from the first region 11s1 toward the first fixed point OB1 and the color of the diffracted light emitted from the second region 11s2 toward the first fixed point OB1 are mutually different. It can be different.

  Further, for example, three or more different values may be included in the cycle d in the pixel 30 that is included in the first region 11s1 and emits the diffracted light toward the first fixed point OB1. The period d in the pixel 30 that is included in the second region 11s2 and emits diffracted light toward the first fixed point OB1 may include three or more different values. Even in such a configuration, the color of the diffracted light emitted from the first region 11s1 toward the first fixed point OB1 and the color of the diffracted light emitted from the second region 11s2 toward the first fixed point OB1 are mutually different. It can be different.

  Note that, in a configuration in which the color of the diffracted light emitted from the first region 11s1 toward the second fixed point OB2 and the color of the diffracted light emitted from the second region 11s2 toward the second fixed point OB2 are different from each other. The configuration may be the same as the configuration described above.

  If the color of the diffracted light emitted from the first area 11s1 and the color of the diffracted light emitted from the second area 11s2 are different from each other, the diffracted light emitted from the first area 11s1 toward each fixed point is different. The colors may be the same, and the colors of the diffracted lights emitted from the second region 11s2 toward the respective fixed points may be the same.

  For example, the first region 11s1 may be composed of the first pixel 31 and the third pixel 33, while the second region 11s2 may be composed of the second pixel 32 and the fourth pixel 34.

  The color of the diffracted light emitted from the first region 11s1 toward the first fixed point OB1 and the color of the diffracted light emitted from the second region 11s2 toward the first fixed point OB1 are the same color. Good. Even with such a configuration, the luminance of the diffracted light emitted from the first region 11s1 toward the first fixed point OB1 and the luminance of the diffracted light emitted from the second region 11s2 toward the first fixed point OB1 are mutually different. If they are different, it is possible to obtain the effect according to the above (2).

  For example, if the first region 11s1 includes the first pixel 31 instead of the second pixel 32, the color of the diffracted light emitted from the first region 11s1 toward the first fixed point OB1 and the second region 11s2 Have the same color as the color of the diffracted light emitted toward the first fixed point OB1.

  In such a configuration, the color of the diffracted light emitted from the first region 11s1 toward the second fixed point OB2 and the color of the diffracted light emitted from the second region 11s2 toward the second fixed point OB2 are mutually different. They may be different or the same.

  For example, in order for the color of the diffracted light emitted from the first region 11s1 toward the second fixed point OB2 to be the same as the color of the diffracted light emitted from the second region 11s2 toward the second fixed point OB2, It is sufficient that the two regions 11s2 include the third pixels 33 instead of the fourth pixels.

  The first region 11s1 and the second region 11s2 display images only toward one fixed point, and even if the colors of the images displayed by the first region 11s1 and the second region 11s2 are different from each other. Good.

  That is, the plurality of pixels 30 forming the uneven surface 11s include a first periodic pixel in which the first convex surface and the first concave surface are arranged in the first period along the arrangement direction, and a second convex pixel along the arrangement direction. And a second concave pixel which is a pixel in which the second concave surface is arranged in a second cycle different from the first cycle. The first region 11s1 includes at least a first periodic pixel, and the second region 11s2 includes at least a second periodic pixel. The ratio of the sum of the areas of the first periodic pixels to the sum of the areas of the second periodic pixels in the first region 11s1, the sum of the areas of the first periodic pixels in the second region 11s2, and the ratio of the second periodic pixels The ratios to the sum of the areas are different from each other.

According to such a configuration, the following effects can be obtained.
(8) Since the color of the light emitted from the first region 11s1 and the color of the light emitted from the second region 11s2 are different from each other, the first region is further compared to a configuration in which the luminance is different between the two regions. The image displayed by 11s1 and the image displayed by second region 11s2 are easily visually distinguished.

  If the plurality of pixels 30 forming the uneven surface 11s include the first periodic pixel and the second periodic pixel, the uneven surface 11s is partitioned into the first region 11s1 and the second region 11s2. It is not necessary.

Even with such a configuration, the effects described below can be obtained.
(9) The display 10 has a different color from the diffracted light emitted from the first periodic pixel and the diffracted light emitted from the second periodic pixel, which is different from the diffracted light emitted from the first periodic pixel. An image composed of the diffracted light can be formed.

  The brightness of the image displayed by the first region 11s1 in the direction in which the display 10 is viewed from the front is different from the brightness of the image displayed by the second region 11s2 in the direction in which the display 10 is viewed from the front. Is also good. According to such a configuration, the display 10 displays an image formed by the first region 11s1 and the second region 11s2 in both the direction in which the display 10 is viewed from the front and the direction in which the display 10 is obliquely viewed. Can be.

  For example, in the uneven surface 11s, if the height H in the first region 11s1 and the height H in the second region 11s2 are different values, the brightness of the image displayed by the first region 11s1 and the second region 11s2 Can change the brightness of the image displayed.

  The uneven structure 11 may have a layer other than the metal layer 42, for example, a layer having a black color, and a layer containing a resin and a dye or a pigment having a black color, as a layer for absorbing light. Even in such a configuration, the light-absorbing layer only needs to be located on the side opposite to the side on which light enters with respect to the uneven surface on which light enters. In order to easily reflect the diffracted light, it is preferable that the display body 10 includes the metal layer 42 as a light absorbing layer.

On the light incident surface of the display body 10, in addition to the above-described uneven surface 11 s, a diffracting portion for diffracting light, a scattering portion for scattering light, and a condensing portion for condensing light are formed. Good.
Among these, the diffraction portion may be the diffraction grating DG described above with reference to FIG. 3 and a diffraction grating DG having a period d that is equal to or longer than the shortest wavelength of visible light.

  In the light scattering portion, for example, a plurality of convex surfaces or a plurality of concave surfaces different in at least one of size, shape, and height along the Z direction are irregularly arranged. The light incident on the light scattering portion is irregularly reflected, and when an observer observes from the light incident side with respect to the light scattering portion, an image having a white color or an image having a cloudy color is visually recognized.

  Of the light scattering portions, the convex surface may have a width along the X direction or the Y direction of 3 μm or more and a height along the Z direction of 1 μm or more. Alternatively, the concave surface may have a width along the X direction or the Y direction of 3 μm or more and a depth along the Z direction of 1 μm or more. The width and height of the convex surface provided in the light scattering portion or the width and depth of the concave surface are larger than the width and height of the diffraction grating provided in the diffractive portion, and are larger than the width and height of the uneven surface 11s described above. Big. In the light scattering portion, if the shape of the convex or concave surface and the direction in which the convex or concave surface is arranged have regularity, directivity can be given in the direction in which light is scattered.

The condensing unit may be configured by a lens such as a micro lens and a Fresnel lens. According to these lenses, light incident on the incident surface of the display body 10 is focused on the light incident side with respect to the incident surface of the display body 10 or on the back side with respect to the incident surface. appear. Therefore, the display 10 can exhibit a visual effect unique to the lens.
Forgery of the display body 10 becomes more difficult when the display body 10 has the diffraction part, the scattering part, and the light collection part.

  An original plate for manufacturing the display body 10 may be formed by a method other than the method described above. For example, a substrate for forming an original plate, for example, silicon, and one surface of a substrate formed of metal or the like is wet-etched or dry-etched, so that an original plate having an uneven surface is formed. It may be formed.

  The article to which the display 10 is attached is not limited to an IC card, but may be another card such as a magnetic card, a wireless card, and an ID (identification) card. Alternatively, the article may be a security such as a gift certificate and a stock certificate, or may be a tag to be attached to an article to be verified as a genuine article, for example, a high-quality article such as an artwork. . Alternatively, the article may be a package or a part of the package that contains the article to be confirmed to be genuine.

  When the base material that supports the display body 10 is formed of paper, the display body 10 is sewn into the paper that forms the base material, and the display body 10 is viewed in a plan view facing one surface of the base material. An opening for exposing the display body 10 to the outside of the base material may be formed in a portion overlapping with. Alternatively, when the base material is formed of a light-transmitting material, the display body 10 may be embedded in the base material, or may be a back surface of the base material, It may be fixed to a surface opposite to a display surface to which different information or the like is attached.

  The display 10 is not limited to the purpose of preventing forgery of an article, and may be used, for example, for the purpose of decorating an article. Further, the display 10 may be used as a toy, a learning material, or the like. In this case, the display 10 itself is an object to be observed.

[Third embodiment]
A third embodiment that embodies the display of the present invention will be described with reference to FIGS. The display according to the third embodiment is different from the display according to the above-described second embodiment in the number of regions constituting the uneven surface. Therefore, in the following, such differences will be described in detail, and configurations common to the second embodiment will be denoted by the same reference numerals as in the second embodiment, and detailed description thereof will be omitted. In the third embodiment, as in the second embodiment, an example will be described in which the pitch and the period on the uneven surface have the same value. Hereinafter, the configuration of the display body and the operation of the display body will be described in order.

[Configuration of display body]
The configuration of the display will be described with reference to FIGS. In FIG. 25, dots are provided on a part of the uneven surface for the purpose of clarifying the distinction between the regions provided with the uneven surface.

  As shown in FIG. 25, the display body 10 has an uneven surface 11s which is a light incident surface, and the uneven surface 11s includes a first region 71, a second region 72, a third region 73, and a fourth region. 74.

  Among these, the first region 71 and the second region 72 are regions that are in contact with each other in the Y direction in plan view facing the uneven surface 11s, and are regions that represent the alphabet “A”. In other words, each of the first area 71 and the second area 72 is an area expressing a part of the alphabet “A”.

  On the other hand, the first region 71 and the third region 73 are regions that are in contact with each other in the X direction in a plan view facing the uneven surface 11s, and are regions that represent the alphabet “B”. In other words, each of the first area 71 and the third area 73 is an area expressing a part of the alphabet “B”.

  The fourth region 74 is a region surrounding the first region 71, the second region 72, and the third region 73 in the uneven surface 11s, and is a region constituting the outer edge of the uneven surface 11s.

  As shown in FIG. 26, the first region 71 includes a plurality of first pixels 31 and a plurality of third pixels 33, and one first pixel 31 and one third pixel 33 extend along the X direction. These two pixels 30 constitute a set of first pixel groups 71g. In the first region 71, a plurality of first pixel groups 71g are arranged along the X direction and are arranged along the Y direction. The first cycle d1 in the first pixel 31 and the third cycle d3 in the third pixel 33 have the same value, for example, 400 nm.

  As shown in FIG. 27, the second region 72 includes a plurality of first pixels 31 and a plurality of fourth pixels 34, and one first pixel 31 and one fourth pixel 34 extend along the X direction. These two pixels 30 constitute a set of second pixel groups 72g. In the second region 72, a plurality of second pixel groups 72g are arranged along the X direction and are arranged along the Y direction. The fourth period d4 of the fourth pixel 34 is, for example, 300 nm.

  As shown in FIG. 28, the third region 73 includes a plurality of second pixels 32 and a plurality of third pixels 33, and one second pixel 32 and one third pixel 33 extend along the X direction. These two pixels 30 form a set of a third pixel group 73g. In the third region 73, a plurality of third pixel groups 73g are arranged along the X direction and along the Y direction. The second cycle d2 of the second pixel 32 is equal to the fourth cycle d4 of the fourth pixel 34, for example, 300 nm.

  As shown in FIG. 29, the fourth region 74 includes a plurality of second pixels 32 and a plurality of fourth pixels 34, and one second pixel 32 and one fourth pixel 34 extend along the X direction. These two pixels 30 constitute a set of fourth pixel groups 74g. In the fourth region 74, a plurality of fourth pixel groups 74g are arranged along the X direction and along the Y direction.

  As described above, the first region 71 and the second region 72, which are regions expressing a part of the alphabet “A”, include the first pixel 31 as the common pixel 30. On the other hand, the first region 71 and the third region 73, which are regions expressing a part of the alphabet “B”, include the third pixel 33 as the common pixel 30. The fourth region 74, which is a region that does not represent either the alphabet “A” or the alphabet “B”, does not include the first pixel 31 and the third pixel 33, and is the other pixel 30. The second pixel 32 and the fourth pixel 34 are included.

[Function of display body]
The operation of the display 10 will be described with reference to FIGS.
As shown in FIG. 30, when the light source LS irradiates the display body 10 with the illumination light IL from a diagonal direction at a predetermined position included in the YZ plane YZ, the observer moves the illumination light IL included in the YZ plane YZ. It is observed from one fixed point OB1, which is on the opposite side to the emission light RL with respect to the front view direction DLV of the display body 10. At this time, the pixels 30 that emit the diffracted light DL toward the first fixed point OB1 are only the pixels 30 having the convex surface and the convex surface extending along the X direction, that is, only the first pixel 31 and the second pixel 32.

  Since the first period d1 of the first pixel 31 and the second period d2 of the second pixel 32 have different values, the diffracted light DL emitted from the first pixel 31 toward the first fixed point OB1 is The color is different from the color of the diffracted light DL emitted from the second pixel 32 toward the first fixed point OB1.

  As a result, when viewed from the first fixed point OB1, the first region 71 and the second region 72 emit the diffracted light DL having the same color toward the first fixed point OB1. On the other hand, the third region 73 and the fourth region 74 have the same color, and the diffracted light DL having a different color from the diffracted light DL emitted from the first region 71 and the second region 72 is used. Injects toward the first fixed point OB1. As a result, the display 10 displays an image composed of an image expressing the alphabet “A” and an image expressing the background of the alphabet “A” toward the first fixed point OB1.

  For example, in the YZ plane YZ, the angle formed by the front view direction DLV and the illumination direction of the illumination light IL is −40 °, and the angle formed by the front view direction DLV and the line of sight of the observer at the first fixed point OB1. Is −60 °. At this time, according to the above equation (2), the first region 71 and the second region 72 emit the orange diffracted light DL toward the first fixed point OB1, and the third region 73 and the fourth region 74. Means that the diffracted light DL having blue color is emitted toward the first fixed point OB1.

  As shown in FIG. 31, when the light source LS irradiates the illumination light IL from a diagonal direction toward the display body 10 at a predetermined position included in the XZ plane XZ, the observer moves the light source LS included in the XZ plane XZ. It is two fixed points OB2 and is observed from the side opposite to the emission light RL with respect to the front view direction DLV of the display body 10. At this time, the pixels 30 that emit the diffracted light DL toward the second fixed point OB2 are only the pixels 30 having the convex surface and the concave surface extending along the Y direction, that is, only the third pixel 33 and the fourth pixel 34.

  Since the third period d3 of the third pixel 33 and the fourth period d4 of the fourth pixel 34 have different values, the diffracted light DL emitted from the third pixel 33 toward the second fixed point OB2 is The color is different from the color of the diffracted light DL emitted from the fourth pixel 34 toward the second fixed point OB2.

  Thus, when viewed from the second fixed point OB2, the first area 71 and the third area 73 emit the diffracted light DL having the same color toward the second fixed point OB2. On the other hand, the diffracted light DL having the same color in the second region 72 and the fourth region 74 and having a different color from the diffracted light DL emitted from the first region 71 and the third region 73 is used. Injects toward the second fixed point OB2. As a result, the display 10 displays an image composed of an image expressing the alphabet “B” and an image expressing the background of the alphabet “B” toward the second fixed point OB2.

  For example, in the XZ plane XZ, the angle formed by the front view direction DLV and the illumination direction of the illumination light IL is −40 °, and the angle formed by the front view direction DLV and the observer's line of sight at the second fixed point OB2. Is −60 °. At this time, according to the above equation (2), the first area 71 and the third area 73 emit the orange diffracted light DL toward the second fixed point OB2, and the second area 72 and the fourth area 74. Means that the diffracted light DL having blue color is emitted toward the second fixed point OB2.

  On the other hand, as shown in FIG. 32, the display body 10 displays an image with reduced brightness, for example, an image having black, toward the third fixed point OB3 which is a predetermined point in the front view direction DLV. . At this time, the brightness of the image displayed by the first area 71, the brightness of the image displayed by the second area 72, the brightness of the image displayed by the third area 73, and the fourth area 74 with respect to the front view direction DLV. Have substantially the same brightness.

  Thus, when the display 10 is viewed from the third fixed point OB3, the image displayed by the display 10 is viewed as one image. As a result, when the display body 10 is viewed from the front view direction DLV, the display body 10 is formed by the image formed by the first region 71 and the second region 72, and by the first region 71 and the third region 73. The image that forms is hidden from the viewer.

  As described above, according to the display of the third embodiment, the following effects can be obtained in addition to the effects (1), (4), and (5) described above.

  (10) The image displayed by the display 10 toward the first fixed point OB1 and the image displayed toward the second fixed point OB2 are different from each other. Therefore, between the image displayed toward the first fixed point OB1 and the image displayed toward the second fixed point OB2, the visual object provided by the display body 10 to the observer is more effective than the configuration in which only the color and the brightness are changed. And the counterfeiting of the display body 10 becomes more difficult.

[Modification of Third Embodiment]
Note that the above-described third embodiment can be appropriately modified and implemented as follows.
The uneven surface 11s only needs to be composed of at least a first region, a second region, and a third region. Even in such a configuration, the first region is composed of the first pixel 31 and the third pixel 33, the second region is composed of the first pixel 31 and the fourth pixel 34, and the third region is the third pixel. With the configuration including the two pixels 32 and the third pixels 33, the following effects can be obtained.

  That is, while an image in which the first area and the second area have the same color is displayed toward the first fixed point OB1, an image in which the first area and the third area have the same color is displayed in the second fixed point OB2. Display toward. Therefore, the display body 10 can display images having one color in the first fixed point OB1 and the second fixed point OB2 in regions different from each other.

  In each of the first region 71 to the fourth region 74, the two types of pixels 30 constituting each region may be alternately arranged along the X direction and may be alternately arranged along the Y direction.

  Each of the first region 71 to the fourth region 74 may include two or more types of pixels having different repetition unit periods as pixels that emit the diffracted light DL toward the first fixed point OB1. Further, each of the first region 71 to the fourth region 74 may include two or more types of pixels having different repetition unit periods as pixels that emit the diffracted light DL toward the second fixed point OB2. According to such a configuration, one region can emit light having mixed colors of different colors toward the first fixed point OB1 and the second fixed point OB2.

The technical ideas grasped from the above-described embodiment and modified examples will be described below as additional notes on the means for solving the problems.
[Appendix 1]
Having a light-transmitting property, an uneven structure layer having an uneven surface on the transmission side,
One of the surface that covers the transmission-side uneven surface and the surface that is in contact with the transmission-side uneven surface and the surface that is opposite to the surface that is in contact with the transmission-side uneven surface is uneven as an incident surface on which light is incident. A metal layer that is a surface, and an uneven structure including
The uneven surface includes a portion where a convex surface and a concave surface are alternately repeated one by one along the arrangement direction,
Each of the convex surfaces extends in a strip shape along an extending direction orthogonal to the arrangement direction, and has a shape that tapers toward a top along a thickness direction of the concave-convex structure, and each of the concave surfaces is Has a shape that extends in a strip shape along the extending direction, and that tapers toward the bottom along the thickness direction of the uneven structure,
In the uneven surface, the light incident on the uneven surface is prevented from being reflected in a direction in which the uneven surface is viewed from the front, and the light incident on the uneven surface is projected in a direction oblique to the uneven surface. On the other hand, a display body in which the convex surface and the concave surface are arranged in a cycle of being emitted from the uneven surface as diffracted light.

  10, 20 ... display body, 11, 21 ... uneven structure, 11a, 21a, 42a, 51a, 52a ... convex surface, 11b, 42b, 51b, 52b ... concave surface, 11c, 42c, 51c, 52c ... top, 11d, 42d , 51d, 52d: bottom, 11s, 21s, 42s, 51s, 52s: uneven surface, 11s1, 71: first region, 11s2, 72: second region, 30: pixel, 31: first pixel, 31a: first Convex surface, 31b: first concave surface, 31c: first top, 31d: first bottom, 31s: first concave and convex surface, 32: second pixel, 32a: second convex surface, 32b: second concave surface, 32c: second top 32d: second bottom, 32s: second uneven surface, 33: third pixel, 33a: third convex surface, 33b: third concave surface, 33c: third top, 33d: third bottom, 33s: third uneven surface , 34... Fourth pixel, 34 a. Convex surface, 34b: fourth concave surface, 34c: fourth top, 34d: fourth bottom, 34s: fourth concave / convex surface, 40: light transmitting layer, 41: concave / convex structure layer, 42: metal layer, 43: support layer, 51 52, original plate, 60 IC card, 61 base material, 61a concave portion, 62 printed layer, 62a through hole, 63 IC chip, 71g first pixel group, 72g second pixel group, 73 Third region, 73g: third pixel group, 74: fourth region, 74g: fourth pixel group, DG: diffraction grating, LS: light source, XZ: XZ plane, YZ: YZ plane, OB1: first fixed point, OB2 ... 2nd fixed point, OB3 ... 3rd fixed point.

Claims (3)

Equipped with an uneven structure having an uneven surface as an incident surface on which light enters,
The uneven surface includes a portion where a convex surface and a concave surface are alternately repeated one by one along the arrangement direction,
Each of the convex surfaces extends in a strip shape along an extending direction orthogonal to the arrangement direction, and has a shape that tapers toward a top along a thickness direction of the concave-convex structure, and each of the concave surfaces is Has a shape that extends in a strip shape along the extending direction, and that tapers toward the bottom along the thickness direction of the uneven structure,
In the uneven surface, the light incident on the uneven surface is prevented from being reflected in a direction in which the uneven surface is viewed from the front, and the light incident on the uneven surface is projected in a direction oblique to the uneven surface. On the other hand, the convex surface and the concave surface are arranged in a cycle of being emitted from the uneven surface as diffracted light,
The uneven structure have a property of absorbing light incident on the concave-convex structure,
The incident side of light with respect to the uneven surface is the observation side,
A predetermined point located on the observation side is a first fixed point, and a predetermined point whose position on the observation side is different from the first fixed point is a second fixed point,
The arrangement direction is a first arrangement direction, the extension direction is a first extension direction, the convex surface is a first convex surface, the concave surface is a first concave surface, and the first arrangement direction The direction intersecting is the second arrangement direction,
The uneven surface is divided into a plurality of pixels,
Among the plurality of pixels, the first convex surface and the first concave surface are alternately arranged along the first arrangement direction, and a pixel that emits diffracted light toward the first fixed point is a first arrangement pixel. ,
The plurality of pixels further include a second array pixel which is a pixel in which second convex surfaces and second concave surfaces are alternately arranged along the second array direction and emits diffracted light toward the second fixed point,
Each of the second convex surfaces extends in a band shape along a second extending direction orthogonal to the second arrangement direction, and has a shape that tapers toward a top along a thickness direction of the uneven structure, Each of the second concave surfaces extends in a band along a second extending direction orthogonal to the second arrangement direction, and has a shape that tapers to a bottom along a thickness direction of the uneven structure. And
In the second array pixel, the light incident on the second array pixel suppresses reflection in a direction in which the second array pixel is viewed from the front, and the light incident on the second array pixel, The peripheral light emitted from the second array pixel as diffracted light in the direction oblique to the second array pixel.
The second convex surface and the second concave surface are aligned in a period,
The uneven surface includes a first region including a plurality of pixels, and a second region including a plurality of pixels.
The first region includes at least the first arrangement pixel, and the second region includes at least the second arrangement pixel,
The ratio of the sum of the areas of the first array pixels to the area of the first region and the ratio of the sum of the areas of the first array pixels to the area of the second region are different from each other. A display body wherein the ratio of the sum of the areas of the second array pixels to the area of one region and the ratio of the sum of the areas of the second array pixels to the area of the second region are different from each other . Equipped with an uneven structure having an uneven surface as an incident surface on which light enters,
The uneven surface includes a portion where a convex surface and a concave surface are alternately repeated one by one along the arrangement direction,
Each of the convex surfaces extends in a strip shape along an extending direction orthogonal to the arrangement direction, and has a shape that tapers toward a top along a thickness direction of the concave-convex structure, and each of the concave surfaces is Has a shape that extends in a strip shape along the extending direction, and that tapers toward the bottom along the thickness direction of the uneven structure,
In the uneven surface, the light incident on the uneven surface is prevented from being reflected in a direction in which the uneven surface is viewed from the front, and the light incident on the uneven surface is projected in a direction oblique to the uneven surface. On the other hand, the convex surface and the concave surface are arranged in a cycle of being emitted from the uneven surface as diffracted light,
The uneven structure has a property of absorbing light incident on the uneven structure,
The period is a first period, the convex surface is a first convex surface, the concave surface is a first concave surface,
The uneven surface is divided into a plurality of pixels,
Among the plurality of pixels, a pixel in which the first convex surface and the first concave surface are arranged in the first cycle along the arrangement direction is a first cycle pixel,
The plurality of pixels further include a second cycle pixel that is a pixel in which a second convex surface and a second concave surface are arranged in a second cycle different from the first cycle along the arrangement direction,
Each of the second convex surfaces extends in a belt shape along the extending direction, has a shape tapering toward a top along a thickness direction of the concave-convex structure, and each of the second concave surfaces is It has a shape that extends in a band along the extending direction, and that tapers toward the bottom along the thickness direction of the uneven structure,
In the second cycle pixel, the light incident on the second cycle pixel is prevented from being reflected in a direction in which the second cycle pixel is viewed from the front, and the light incident on the second cycle pixel is the second periodic pixel said second convex surface and the second concave and is parallel beauty in the second period of injection from the second period pixel as diffracted light with respect to a direction oblique to,
The uneven surface includes a first region including a plurality of pixels, and a second region including a plurality of pixels.
The first region includes at least the first periodic pixel, the second region includes at least the second periodic pixel,
The ratio of the sum of the areas of the first periodic pixels in the first region to the sum of the areas of the second periodic pixels, the sum of the areas of the first periodic pixels in the second region, and the Different from the sum of the area of the two-period pixels
Table示体. In the front view direction, the brightness of the image displayed by the first region in the front view direction is substantially equal to the brightness of the image displayed by the second region in the front view direction. so as to display body according to claim 1 or 2, wherein the uneven surface is formed.